The displacement of diamonds during brazing is a critical issue in brazed diamond tools, as it directly compromises the tool's dimensional accuracy and machining quality. Nickel-based filler alloy brazed tools often exhibit excessive wetting, which promotes abrasive displacement and diamond over-embedding, thereby degrading overall performance. This study addresses these limitations by adding 304L stainless steel powder into Ni-Cr-P to modulate molten filler alloy fluidity and wetting behavior. Through the improved strategy, the diamond tool was obtained with well-ordered abrasive distribution and appropriate exposure. The interfacial microstructure and mechanical properties of 304L/Ni-Cr-P brazed diamonds were characterized using Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), shear testing, and friction-wear analysis. The results reveal that the addition of 10-30 wt% 304L effectively suppresses diamond agglomeration, while reducing displacement to 25.13 mu m (20.9 % of the grit diameter) and enhancing abrasive protrusion by 70.72 % through filler fluidity control. However, 304L additions exceeding 20 wt% thins the interfacial Cr3C2 reaction layer, lowering shear strength by 53.7 %. Optimal 10-20 wt% 304L balances wear resistance and material removal efficiency while processing with low rates of uneven wear. This work advances high-performance brazed diamond tool manufacturing by optimizing filler alloy composition to suppress abrasive displacement and control diamond exposure, thereby enhancing machining efficiency and stability for demanding applications.

The rapid wear of grinding tools and severe workpiece damage during machining of 2D-C f/C-SiC ceramic matrix composites (CMCs) remain critical challenges. Additive manufacturing of Laser Powder Bed Fusion (LPBF) offers a transformative opportunity to address this issue by producing grinding tools with precisely controlled complex internal structures, yet there is still a lack of design basis. To address these issues, this study proposes a function-driven design mapping strategy and investigates the structure-performance relationship of porous structured diamond wheels fabricated by Laser Powder Bed Fusion (LPBF). Solid and four typical lattice structures (TPMS-Gyroid, TPMS-Diamond, BCC, TO) with porosities of 20%-50% were manufactured and evaluated via grinding experiments, mechanical experiments, and CFD simulations. Results show that grinding performance is dominated by the synergistic effect of porosity and topology. The Gyroid-30 structure achieves the lowest surface roughness (Ra approximate to 530 nm) owing to excellent damping and heat dissipation. Triply Periodic Minimal Surface (TPMS) topologies exhibit superior cooling performance, and the deformation mechanism varies with porosity. Application-oriented guidelines are established: Gyroid (30-40%) for fine grinding, BCC/TO (20-30%) for rough grinding, and Gyroid (30-50%) for drilling. This work provides a theoretical and practical basis for the performance-driven design of next-generation additive manufacturing grinding tools for CMCs.

The fabrication of cubic boron nitride-reinforced metal matrix composites (cBN-MMCs) with complex structures for high-performance grinding tools remains constrained by conventional techniques. In this study, a cBN-MMC was fabricated for the first time via laser powder bed fusion (LPBF) using a CuNiFeSnTi high-entropy alloy (HEA) as the metal matrix. The influence of process parameters on the formability, microstructure, and properties of the composites was systematically investigated. A TPMS-structured grinding wheel based on the Schwarz Diamond surface (TD-GW) was designed, fabricated, and evaluated in grinding experiments on FGH96 superalloy. The results demonstrate that cBN particles restricted melt pool flow, leading to lack-of-fusion (LOF) pores and increased porosity. Significant particle spattering during processing markedly reduced the cBN content, with scanning speed exhibiting a particularly pronounced effect. At the interface, a TiN reaction layer and a Ti segregation layer were formed, where a thin segregation layer enhanced bonding but excessive thickness promoted microcracking. The composite exhibited progressive damage under load due to defects such as pores, unmelted powder and cracks. Compared with a traditional grinding wheel (Tra-GW), the TD-GW reduced tangential grinding force by 53.9%, grinding temperature by 41.7%, and workpiece Ra by 12.5%, attributed to improved cooling and chip evacuation. This study provides process guidance and theoretical support for the additive manufacturing of structured cBN-MMC grinding wheels.

Silicon carbide (SiC) is widely used in power semiconductor devices due to its wide bandgap, high thermal conductivity, and high breakdown electric field strength. However, its high hardness, brittleness, and chemical stability pose challenges for efficient and low-damage machining. Laser-assisted machining provides a promising strategy for improving the machinability of SiC, but the role of laser-modified layers in governing the surface response and damage evolution remains insufficiently understood. In this study, nano-scratching experiments, tribological tests, and molecular dynamics (MD) simulations were conducted to investigate the material removal and subsurface damage suppression mechanisms of laser-modified 4H-SiC surfaces. The results demonstrate that laser fluence and overlap rate strongly influence the types and structural dimensions of laser-induced periodic surface structures (LIPSS). High-spatial-frequency LIPSS (HSFL) formed under high-overlap conditions exhibits the most pronounced hardness reduction. Compared with the pristine surface, the laser-modified layer shifts the removal mode from severe brittle fracture to ductile removal and confined fracture of the LIPSS, thereby protecting the underlying substrate. Experimental observations and MD simulations reveal that the laser-modified layer reduces the peak stress, promotes near-surface amorphization and polycrystallization, mitigates stress concentration caused by multi-slip interactions, and suppresses subsurface crack formation. MD simulations further clarify the independent roles of the amorphous layer and periodic surface structures. These findings deepen the mechanistic understanding of the removal behavior of laser-modified layers and provide guidance for efficient and low-damage processing of hard-brittle semiconductor materials.

In present, high contents of Al2O3 mixed in TC4 matrix composites for selective laser melting complex components faces the issues of easy-cracking and hard formation. This work presents an comprehensive investigations about the defect formation mechanisms of selective laser melted Al2O3/TC4 composites via numerical and experimental analysis. The research route includes following points: I. molten pool morphology changing rules and temperature history influenced by laser power and laser scanning speeds; II. molten pool evolution process analysis using a multi-physics numerical simulation model and experimental observations; III. defects formation mechanism analysis by observing movements tendency and interface combination of melted TC4 alloy and Al2O3 particles. From these results, the laser processing parameters significantly influence the morphology of the molten pool, which is fundamentally attributed to variations in energy density; differences in physical properties result in the inability of Al2O3 to melt and establish robust interfacial bonding with TC4 during the SLM process; unmelted Al2O3 particles exhibit agglomeration behavior under the combined effects of the molten pool driving forces and Van der Waals forces; poor wettability and chemical incompatibility between two materials weaken the interfacial bonding between Al2O3 particles and TC4 molten pool, thereby promoting the formation of microcracks. This work help to understand the defect formation and provides an optimization method of SLM process parameters for selective laser melted Al2O3/TC4 composites components.

The rapid advancement of next-generation microelectronics and high-power density laser systems has imposed rigorous demands on thermal management materials. Diamond/Cu composites have emerged as promising candidates for heat sink applications; however, their effective thermal conductivity (keff) often deviates substantially from theoretical predictions. This discrepancy primarily arises from pronounced interfacial thermal resistance caused by severe phonon vibrational mismatch. In this study, we present a comprehensive theoretical and experimental investigation of Diamond/Cu composites fabricated via vacuum hot-pressing sintering. To accurately represent the thermal transport behavior, a modified Bruggeman effective medium theory is proposed, incorporating a size-dependent correction function and a global interfacial efficiency factorη. This model effectively characterizes the competition between geometric boundary reduction and the solid-state contact penalty. Based on experimental data for 30 vol% and 40 vol% diamond fractions, the global model demonstrates high predictive accuracy (MAPE = 4.39%),and the optimal theoretical particle size (dopt) for uncoated systems was determined to be approximately 545.3 μm. Further, the derived global values (η ≈ 0.1500) provide strong quantitative evidence that interfacial thermal resistance is the primary bottleneck limiting macroscopic heat transfer. The consistency of (η) across different volume fractions suggests that the thermal bottleneck is intrinsic to the Diamond/Cu interface. This analysis establishes a scalable theoretical framework for the rational microstructural design of high-performance thermal management architectures.

Porous diamond grinding tools fabricated by selective laser melting (SLM) can provide space for coolant flow and chip removal, but the effects of cellular structure type and porosity on their comprehensive performance have been rarely investigated. In this work, three structural design approaches, including triply periodic minimal surface (TPMS), topology-optimized, and bio-inspired structures, were used to design porous Cu-based bonded diamond tools, which were fabricated by SLM. Structures with different porosities were investigated, and specimens with a common porosity of 50% were used for direct comparison among different cellular structure types. Their performance was evaluated by compression, permeability, and grinding tests. Finite element analysis was used to reveal stress distribution and deformation behavior, and the Kozeny-Carman equation was introduced to describe the relationship between porosity and permeability. The fabricated structures showed acceptable forming accuracy, and no obvious graphitization of diamond was observed. Compression tests showed that elastic modulus and yield strength decreased with increasing porosity, while the fracture mode changed from 45 degrees shear fracture to layer-by-layer fracture. At 50% porosity, the topology-optimized structure exhibited the best compressive properties, while the Schoen I-WP structure showed the best permeability. Grinding tests showed that material removal rate and grinding ratio generally decreased with increasing porosity, and the bioinspired snake structure exhibited the highest grinding ratio among the bio-inspired structures. Finally, a structure-property map was developed to guide cellular structure selection for different functional regions of porous diamond grinding tools.

Fixed abrasive lapping, as a typical precision machining method, is widely applied in various fields such as ceramics, optical crystals, metals, and semiconductor materials. In the lapping process, the lapping plate, serving as the core tool, plays a decisive role in determining both processing efficiency and machining quality. In this study, a modularly spliced diamond lapping plate with a high-entropy alloy binder was fabricated using selective laser melting (SLM) technology, and its basic forming quality and abrasive grain distribution characteristics were evaluated. Lapping experiments on sapphire wafers were conducted under typical processing parameters to analyze material removal efficiency, surface roughness variation, and tool wear. The results show that the lapping plate manufactured by SLM have excellent moulding accuracy with an average abrasive grain distribution density of 30 grains per square millimetre and a distribution coefficient of variation of 0.3. The maximum material removal rate for sapphire wafers reached 6.36 mg/min, and the minimum surface roughness was approximately 150 nm. These findings validate the feasibility and engineering potential of using SLM for the fabrication of high-performance precision lapping tools.

Ordered arrangement brazed diamond tools offer enhanced machining efficiency by enabling controlled distribution and exposure height of diamond. However, during the brazing process, variations in process parameters can affect the wettability between the brazing alloy and diamond, resulting in different brazing morphologies. In this study, a computational fluid dynamics (CFD)-based brazing simulation model was built to investigate the effects of temperature and heating rate on exposure height of Cu-20Sn-10Ti alloy and displacement of diamond. The simulation and experimental results both demonstrate that with the increase of temperature, the exposure height of diamond decreases gradually, while the change of particle spacing increases due to excessive wetting. With the increase of heating rate, the exposure height increases first and then decreases, while the change of particle spacing is opposite. The brazing alloy undergoes three stages: solid state, solid-liquid coexistence state and complete liquid state. In the complete liquid state stage, the wettability behavior between alloy and diamond significantly impacts capillary force and interfacial bonding force, which ultimately determine the exposure height and displacement of diamond. To ensure a higher diamond exposure height and reduced particle displacement of the diamond conditioner applied in the semiconductor industry, the optimized brazing temperature is 880 degrees C and the heating rate is 5 degrees C/min. This study advances the understanding of wetting-driven morphological evolution of the brazing alloy during vacuum brazing, and provides a scientific basis for optimizing temperature and heating rate to manufacture high-performance ordered arrangement diamond tools.

The deflection of diamond wire saws—commonly referred to as wire bow—during stone machining significantly compromises the geometric accuracy of curved surfaces and corner regions, often resulting in the rejection of workpieces. To address this issue, we propose a systematic parameter optimization strategy that minimizes wire bow while maintaining a high feed rate. Initially, the relationship between machining parameters and wire deflection is theoretically established using a macroscopic mechanical model. A laser-based measurement system is then developed to quantify three novel evaluation metrics: average deflection (D), maximum deflection (H), and cross-sectional deformation area (S). The Taguchi method and analysis of variance (ANOVA) are employed to determine the primary effects of machining parameters on these metrics. Three machine learning models—generalized regression, backpropagation neural network (BPNN), and support vector regression (SVR)—are used to predict D, with the SVR model achieving the highest predictive accuracy (R2 = 0.984). Based on these predictive models, an optimal parameter combination is derived and experimentally validated. The results show that, under a feed rate of 12 mm/min, the optimized parameters reduce corner-cutting error by 49.62

Zirconia ceramics (ZrO2) are widely used in various industries due to their exceptional mechanical properties and chemical stability. However, their inherent high hardness and brittleness pose significant challenges during grinding processes. In this work, textured grinding wheels (TGWs) featuring a spiral structure were designed for grinding zirconia ceramics. TGWs with different helix angles were additive-manufactured by selective laser melting (SLM). The grinding performance of these TGWs was evaluated and compared with that of a conventional non-textured grinding wheel (Non-TGW). Numerical simulations were conducted to analyze the flow characteristics of the coolant at the TGW/workpiece interface. The experimental results revealed that spiral TGWs significantly reduce grinding forces and temperatures, leading to improved material removal rates and surface quality. The 30 degrees-TGW achieved a reduction in temperature by 39.09 % and a decrease in surface roughness by 42.49 %. These improvements were significant due to the enhancement of the cooling condition and chip removal (the 30 degrees-TGW achieved a 29.64-fold increase in overall mass flow rate and a 1.95 fold rise in end-face flow rate compared to the Non-TGW). A coefficient of QEGA was introduced to further analyze the relationship between grinding performance and helix angle. Finally, a functional partition map of high machinability and abrasion resistance was obtained for guiding the design of spiral-TGW. This work offers a comprehensive guide for designing TGWs tailored to specific industrial requirements, thereby advancing the field of ceramic machining.

Selective laser melting (SLM) is considered an effective technology in fabricating high-performance metalbonded diamond tools with integrated internal cooling and chip evacuation channels. However, the formation of certain defects during the SLM process significantly compromises the mechanical properties and service life of diamond tools. Defect generation exhibits a strong correlation with laser processing parameters, among which laser hatch spacing constitutes a critical factor governing successful laser spot overlapping between adjacent molten tracks. To investigate the defect formation mechanisms, this work establishes a double-track multi-scale phase transition-multiphysics coupled model for diamond/CuSn20 composites. Through integrated CFD-based numerical simulation and experimental approaches, the effects of hatch spacings variations on molten pool evolution, defect generation mechanisms, and mechanical properties of diamond-metal composites were investigated. The principal findings are as follows: (1) Residual temperature from the first molten track modifies the initial temperature of the second molten track. Simultaneously, the temperature gradient generated by the second laser pass induces remelting of the overlapping. (2) At reduced hatch spacing, thermal damage preferentially occurs in diamond grits, whereas enlarged hatch spacings promote pore formation, unmelted zones, and interfacial gaps in overlapping regions. (3) Specimens fabricated at an 80 mu m hatch spacing exhibit the highest compressive strength. Although their COF initially exceeds that of 100 mu m-spaced specimens, it decreases below the latter's COF after 14 min of testing. This work provides a systematic analysis of diamond migration behavior and molten pool defect genesis during melting-solidification processes.

High-performance piezoelectric poly(vinylidene fluoride) (PVDF) has great application potential in the field of microsensors, but achieving efficient polarization remains a challenge. Here, the in situ doping electrospinning technique is employed to enhance the piezoelectric properties by introducing a single dose of zinc oxide (ZnO) or barium titanate (BaTiO3,BTO) dopants. The effects of key processing parameters on the morphology of nanofiber membranes were systematically investigated. In addition, the influence of zinc oxide (ZnO) or barium titanate (BTO) dopant concentrations on the piezoelectric properties of PVDF was examined. The microstructure, electrical performance, and β-phase content of the composite membranes were characterized. Results indicate that the composite film with a doping formulation of 16 wt% PVDF and 10 wt% ZnO exhibits optimal overall performance: the β-phase content of PVDF reaches 52.8%, and the output voltage reaches 1.5 V, which is 2.5 times higher than that of the undoped PVDF nanofiber membranes. This study provides an effective doping strategy for the fabrication of high-performance piezoelectric nanofiber membranes.

ObjectiveSelective laser melting (SLM)technology provides a new approach for the integratedmanufacture of metal-matrix diamond tools with structural and functional integration, which has drawn alot of interest from the academic and technicalcommunities. The powder spreading process is the keyprocess of SLM technology, which is very important toobtain a dense, flat and uniform powder bed. However,there are defects such as pits, scratches, loose packing ofpowder bed, uneven distribution of powder layer, andparticles segregation in the powder spreading process.Further research is required since the powder spreadingprocess of metal-based diamond composite powdermaterials entails intricate scientific and engineeringissues such as non-spherical particles and multicomponentpowders. In this work, three blades of linear,circular, and parabolic as well as roller spreaderstructures are selected to explore the influencemechanism of spreader structures on the powderspreading quality and particle dynamic behavior.Research results have guiding significance for theoptimization of powder spreading processes of metalmatrixdiamond tools in SLM.MethodsIn order to achieve the aforementionedobjectives, the diamond/CuSn powders were utilized asthe research object to build the three-dimensionalgeometry of two types of powders. In this work, theadhesion force was introduced into the particle contactdynamics model, which was based on the Hertz-Mindlinmodel and Johnson-Kendall-Roberts (JKR) theory. Adiscrete element model (DEM) describing the microforceof two kinds of powder particles was established.The DEM of powder spreading process was constructed,and three blades of linear, circular, and parabolic as wellas roller spreader structures were selected. Parametricequations were used to alter the spreader's geometricshape. It has been investigated how the spreaderstructural factors affect the powder bed's density and thediamond distribution's homogeneity. The particledynamic behavior and the mechanism of powder beddensification in the powder spreading process wereexplored. Furthermore, the physical mechanism ofparticles segregation and jamming in the process ofpowder spreading were revealed.Results and DiscussionsFirst, the influence ofspreader structures on the powder bed quality wasexamined. When the structural coefficient angle θ of thelinear blade increased from 0° to 90° , the powder spreading quality changed slightly. As the angle θincreased from 90° to 150° , the powder spreadingquality was significantly improved. The powderspreading quality was significantly improved as thestructural coefficient c of the circular blade increasedfrom 0.25 mm to 1.25 mm. When the structuralcoefficient p value of the parabolic structure increasedfrom 0.1 to 2, the relative bulk density decreased from0.36 to 0.29, and the standard deviation increased from0.031 to 0.041. Increasing the diameter of the roller canimprove the powder bed quality. Under the condition ofthe structural parameter optimization given in this work,the influence of spreader structures on the powder bedquality was comprehensively considered. The resultsshowed that the powder spreading quality of parabolicblade and roller spreaders was relatively good, thecircular blade was the second, and the linear blade wasrelatively poor. Second, the flow behavior of particleswas analyzed. With the translational motion of thespreader, the upper part of the powder pile was shearedand moved forward under the action of the spreader. Theparticles in the lower part of the powder pile passingthrough the gap between the spreader and the substratewere similar to particles flowing through the orifice ofthe conical hopper. In addition, the particles underwentcomplex diffusion and cyclic movement inside thepowder pile due to the complex movement of the roller.While the diffusion movement of particles inside thepowder pile was relatively weak during the blade'spowder spreading process. The structure of the bladespreader had a slight effect on the trajectory of particles.The trajectories of diamond and CuSn particles showedsimilar flow patterns. The particles driven by thespreader moved horizontally and rose, fluctuating adistance at a high position. Particles then avalancheddown the powder heap's slope as a result of gravity.Ultimately, the particles through the gap between thespreader and the substrate were deposited on thesubstrate. Then, the particle contact force chains wereexamined. With the increase of θ value and c value, andthe decrease of p value, the blade exerted an obliquedownward pressure on particles, increasing their normalcontact force and lessening the blade's shear effect onthem. This would improve the powder bed quality. Forthe roller spreader, increasing the diameter of the roller would increase the area of interaction between the rollerand the powder pile, which would increase the normalcontact force of particles, strengthen the compactioneffect of the roller and improve the powder bed quality.Finally, the volume fraction of diamond particles wasanalyzed in terms of its spatial distribution. There wasno significant difference in the effect of spreaderstructures on the volume fraction of diamond particles inthe X direction, but the volume fraction of diamondparticles first increased exponentially along the Xdirection before fluctuating about the predeterminedvalue. This demonstrated that there was particlessegregation due to the low concentration of diamondparticles close to the front of the powder bed. Theprimary cause was that the fine CuSn particles weremore likely to pass through the gap between thespreader and the substrate, and deposited on the front ofthe powder bed. While the coarse diamond particleswith irregular shapes created strong force chains that caused particle jamming.ConclusionsWith the increase of the linearstructure angle θ value and the circular structurecoefficient c value, the decrease of the parabolicstructure coefficient p value and the increase of theroller diameter d, the oblique downward pressure of thespreader on particles is enhanced which will increase thenormal contact force of particles. And the shear effect ofthe spreader on particles is weakened, therebyimproving the powder bed quality. The results show thatthe powder spreading quality of parabolic blade androller spreaders is relatively good, the circular blade isthe second, and the linear blade is relatively poor. Thevolume fraction of diamond particles first increasedexponentially along the X direction before fluctuatingabout the predetermined value, resulting in the diamondparticles segregation during the powder spreadingprocess.

In face of extreme processing environments, highly complex parts and hard-processing materials, the next generation of diamond tools not only are required to have good grinding performance, but also enough space of accommodating chips and certain strength. The structure-function integrated design and manufacturing of diamond tools driven by processing requirements is an effective way to deal with the above challenges. In this work, a series of triply periodic minimal surface (TPMS) porous metal-bonded diamond specimens with different porosities from 30 % to 70 % were fabricated by Selective Laser Melting. Morphological observations, compressive test, permeability test and grinding test of SLM-fabricated specimens were carried out. Experimental results indicate that the SLM-fabricated specimens have a good agreement in geometry morphology with designed 3D models. The yield strength and elastic modulus decrease gradually with the increase of porosity, and the failure mechanism changes from the diagonal shear failure to layer-by-layer fracture. Additionally, Darcy's law were applied to evaluate the permeability of porous specimens. Also, the relationship between porosities and permeability properties of porous specimens were established. Finally, the grinding test shown that the SLMfabricated uniform grinding tools with 50 % porosity (U-50 %) had excellent grinding performance that can obtain higher quality workpieces comparing to full-dense grinding tools. In addition, the gradient porosity grinding tool (G-(50 %-60 %)) has a stable grinding force while reducing the roughness of the machined workpiece from 1.06 nm to 0.76 nm, an improvement of 28.3 %. This work provides an important technical reference for the design and manufacturing of high performance metal-bonded diamond tools.

In this research, to enhance the high-temperature hardness of Ti6Al4V, composites reinforced with Al2O3 and ZrO2 eutectic mixtures were fabricated via selective laser melting (SLM). Varying contents of Al2O3-ZrO2 content from 0 wt% to 2.0 wt% were added to pure Ti6Al4V to prepare composite powders for SLM. The effect of the Al2O3-ZrO2 content on the relative density, microstructure and hardness properties of Ti6Al4V was investigated. The relative density of SLM-fabricated composites was measured via Archimedes' principle. The microstructure was characterized by SEM, XRD and EBSD. The hardness properties were tested by a micro-sclerometer at room temperature, and high-temperature tests were conducted from 200 degrees C to 800 degrees C using a Vickers hardness tester. The SLM-fabricated composites with relative densities greater than 93.45 % can be obtained by optimizing process parameters. The microstructure of the composite varied from a dendritic structure (0.4 wt%) to a needle-like structure (2.0 wt%), which is attributed to the role of Al2O3-ZrO2 particles as nucleating agents and the influence exerted on the solidification process. The grain size decreases with increasing Al2O3-ZrO2 content, which contributes to enhanced strength and hardness. The high-temperature hardness of composite gradually decreases as the temperature increases from 200 degrees C to 800 degrees C. However, Ti6Al4V with 2.0 wt% Al2O3-ZrO2 retains a hardness of 327.64 HV at 800 degrees C, which remains within the acceptable range for the hardness requirements of industrial fields. The enhancement of Ti6Al4V with Al2O3-ZrO2 eutectic mixture particles significantly improves its hardness, especially at high temperatures, offering potential for widespread application in aerospace, automotive, and energy industries.

Selective laser melted (SLMed) porous metal-bonded diamond grinding tools have been proved to own abundant chip storage space and good self-sharpening property. SLMed porous CuSn20-bonded diamond tools were systematically investigated to elucidate the influence of Uniform Lattice Structures (ULS, UL-30 %-50 % porosity) and Functionally Graded Lattice Structures (FGLS, GL-P and GL-V) on compressive behaviour and grinding performance in this work. Gyroid type cellular architectures were designed in MATLAB, fabricated via SLM with CuSn20 alloy and diamond (15 vol%), and characterised by SEM, EBSD and Raman spectroscopy. Quasi-static compression and finite element method revealed that ULS specimens exhibited porosity-dependent elastic modulus (1469.32-648.5 MPa) and compressive strength (47.83-19.78 MPa), with failure mode transitioning from 45 degrees shear-dominated (UL-30 %) to layer-by-layer bending-dominated (UL-50 %). The Gibson-Ashby model accurately predicted ULS properties (R-2 > 0.99), whereas Kelvin-Voigt and iso-stress models estimated FGLS modulus within 11 % but over-predicted strength due to brittle interfacial fracture. Grinding BK7 glass with ULS tools (UT-30 % to 50 %) demonstrated decreased material removal rate (MRR) (314.04-285.76 mm(3) min(-1)) and wear ratio (WR) (28.81-25.47) with increasing porosity. In contrast, FGLS tools (GT-P1, P2) achieved superior MRR (327.15 mm(3) min(-1)), WR (96.12 and Ra (1002 nm) by synergistically combining dense G-region for grinding and porous R-region for chip removal, thereby mitigating stress concentration and extending tool life. These findings provide a quantitative basis for tailoring gradient porosity in SLMed diamond tools and applicable to high-precision machining of optical glass, brittle alloys and ceramic bearings.

HPHT-synthesized polycrystalline diamonds (PCD) exhibit ultrahigh hardness, widely used in cutting and drilling tools. The mechanical strength, primarily dependent on diamond skeleton formation, is significantly influenced by the alloy binder. In this study, PCDs were prepared using 3 multi-component alloy binders: Co60Ni30Cr6C4, (Co60Ni30Cr6C4)94Ti3Al3, and (Co60Ni30Cr6C4)90Ti2.5Zr2.5Al5 under HPHT conditions. The results show that (Co60Ni30Cr6C4)90Ti2.5Zr2.5Al5-PCD achieves the highest transverse rupture strength (approximately 891 MPa), which is 35.6 % and 13.8 % higher than that of Co60Ni30Cr6C4-PCD and (Co60Ni30Cr6C4)94Ti3Al3-PCD, respectively. This improvement is attributed to the formation of a well continuous and interconnected diamond skeleton, most probably facilitated by increased generation of fine diamond grains which effectively bridge these particles. Additionally, the carbides formed under HPHT conditions in the (Co60Ni30Cr6C4)90Ti2.5Zr2.5Al5-PCD can strengthen diamond-binder interfacial bonding. This study provides useful insights for designing new alloy binder to synthesize PCD under HPHT while also deepening the understanding of the formation mechanisms of the diamond skeleton within PCD.

This study established a simulation model for abrasive water jet rock breaking based on the SPH-FDEM method. The effects of abrasive concentration and jet velocity on crack and energy consumption were investigated based on the model. The effect of finite and infinite element boundaries on simulation results was compared, and it was found that the infinite element boundary can mitigate the damage caused by stress wave reflection on rocks. During water jet rock breaking, the crack mode inside the rock was dominated by Mode-I crack (opening-mode crack) due to the water wedge effect, and the number of cracks and the broken volume increased with increasing velocity and abrasive concentration. In this study, the specific energy consumption (SEC) was used to evaluated the rock-breaking capacity. Under pure water jetting, the SEC decreased with increasing velocity, while with the addition of abrasive, the SEC increased with increasing velocity and abrasive concentration. These findings provided a basis for optimization of water jet machining parameters in engineering applications.

Diamond/SiC composites have emerged as a new generation of highly promising materials for semiconductor packaging due to their excellent thermal conductivity. However, the exceptionally hard diamond and SiC phases in the composites have made precision machining a substantial difficulty. This study specifically explores the utilization of ultrasonic-assisted lapping (UAL) to enhance the machining performance of diamond/SiC composites. The focus is on investigating the effects of UAL on the material removals, including the brittle-ductile transition of sample interfacial diamond at different ultrasonic conditions, as well as the surface morphology of diamond/SiC composites. The removal mechanism of diamond/SiC composites under different machining conditions and the transient impact action of the abrasive were systematically analyzed, taking into account the abrasive size, the mechanical effects of ultrasonic vibration, and the interplay of processing parameters. The experimental results reveal that UAL significantly changes the traditional removal mode of diamond/SiC composites. At a constant rotational speed, the diamond abrasive size in the lapping solution exerts the primary influence on the sample surface morphology, followed by the average power of ultrasonic. Compared to conventional lapping methods, UAL improves the removal rate by 10.3 %, 5.4 %, and 5.3 % for abrasive sizes of 8 mu m, 4 mu m, and 1 mu m, respectively. Optimally, the best surface quality finish of diamond/SiC composites was achieved with a lapping solution containing 4 mu m abrasive particles and an average ultrasonic vibrator power of 75 W. This study underscores the potential of UAL to enhance the efficiency and quality of diamond/SiC composite machining.