Brass alloys usually have excellent corrosion resistance, but inadequate wear resistance due to low hardness, which limits their high-end applications. It is an effective strategy to enhance the wear resistance by significantly refining the brass grains to increase the hardness. Whereas it is still of great challenge for fabricating ultrafinegrained brass alloys via hot working process owing to their quick recrystallization and grain growth. In this study, enhanced grain refinement of CuZn30 brass with trace microalloying elements P, Ni, and Ag (total content of 0.018 wt%) was successfully realized after two-pass continuous extrusion deformation. The microstructure evolution especially the characteristics of dynamic recrystallization and its effect on mechanical properties were then studied. The results showed that the microalloyed CuZn30 alloy achieved a greatly refined microstructure with an average grain size of 0.97 & micro;m after two passes continuous extrusion, compared with 14.33 & micro;m for the normal CuZn30 alloy. It was found that microalloying effectively inhibited the discontinuous dynamic recrystallization behavior, which in turn triggered the continuous dynamic recrystallization during the continuous extrusion process. Such a transition in the dynamic recrystallization mechanism is closely related to the addition of microalloying elements, which alter the dislocation movement behavior, and promote the formation of dense subgrain structures. With enhanced grain refinement, the microhardness increased from 92.96 HV to 180.83 HV correspondingly, with only a slight decrease in electrical conductivity. These results show that the hardness of brass alloys has been significantly improved by microalloying and industrially available deformation processes, which has considerable application potential for improving wear resistance and broadening high-end applications.

Achieving a synergistic enhancement of hardness and electrical conductivity in Cu-Ni-Si alloys requires precise modulation of nanoprecipitation. Although Co and Cr microalloying are established strategies, their underlying mechanisms, particularly the role of chemical short-range order (CSRO), remain unclear. Contrary to expectations, introducing Co and Co-Cr into a Cu-Ni-Si alloy increased hardness but decreased electrical conductivity. Atomic-scale characterization and computational analysis revealed, for the first time, that Co induces a distinct Cu-Co CSRO. This CSRO traps Si solutes, impeding the nucleation and growth of the primary strengthening delta-Ni2Si nanoprecipitates. The retained disordered Ni and Si atoms, along with the CSRO itself, degrade conductivity. Furthermore, Co and Cr regulate nanoprecipitates differently: Co stabilizes the precipitate-matrix interface, refining delta-(Ni,Co)2Si and suppressing coarsening, while Cr segregates at the precipitate core, exerting a kinetic drag effect. Both elements synergistically enhance coarsening resistance. This work clarifies the dual, strengthening-yet-conductivity-limiting role of Co-induced CSRO and the distinct, synergistic mechanisms of Co and Cr in nanoprecipitate modulation.

For the manufacturing of the wick of a vapor chamber, although the Selective Laser Melting (SLM) technology offers the freedom to design structures and gradients, it is limited by the laser spot diameter, making it difficult to precisely control the micropore diameters. This study adopts a novel modeling strategy, which controls the pore characteristics by adjusting the relative relationship between the unit length and the wall thickness of cubic structural units to achieve the best balance between capillary force and permeability. By characterizing the pore characteristics and capillary suction performance (capillary force and permeability) of the printed samples, a predictive model of the relationship between the geometric parameters of the unit and the structural performance was established. The research found that the quantitative relationship between the unit length to the wall thickness determines the pore diameter and porosity of the porous structure, which in turn has a critical impact on the fluid transport performance of the wick. This study demonstrates the feasibility of using the SLM process to prepare high-performance customized wicks, has quantified the relationship between the structural unit size parameters and functional performance for the first time, and provides a reference for the structural optimization design and precise manufacturing of the wick of a vapor chamber.

Bending performance serves as a critical indicator for assessing the formability of copper alloy strip products. This study presents a novel bending test methodology incorporating quantitative evaluation parameters to systematically analyze copper alloy strips deformation behavior. Through comprehensive microstructural characterization of bent specimens, we established a direct correlation between bending surface quality and characteristic features in the force-displacement curve. The investigation further revealed the progressive evolution of surface defects under varying reduction ratios during bending deformation. The developed methodology demonstrates that the bending surface quality can be accurately identified through mechanical curve analysis without requiring microscopic examination, enabling efficient and reliable non-destructive evaluation. This advancement provides an industrially viable solution for real-time quality control of bending performance during production processes.

Laser heat treatment (LHT) was employed to achieve rapid quenching of an Al-Cu-Mg alloy. The mechanical properties, microstructural evolution, and precipitate characteristics under different LHT conditions were systematically investigated. The results showed that LHT with peak temperatures above 450 °C significantly improved the mechanical strength of the alloy but not exceeding 580 °C to avoid grain boundary melting. With increasing laser temperature, no obvious changes in grain orientation, texture, or grain size were observed, whereas the morphology and distribution of precipitates evolved considerably. Unlike conventional furnace heat treatment, which predominantly produced uniformly dispersed nanoscale S′ precipitates within grains, LHT generated fewer intragranular S′ precipitates but induced a unique continuous chain-like S′ phase along grain boundaries, accompanied by the formation of precipitation-free zones. The volume fraction of these grain-boundary precipitates increased markedly with rising laser temperature. This distinctive precipitation behavior contributed to a novel strengthening mechanism. Quantitative analysis based on theoretical models revealed that the chain-like S′ phases contributed up to approximately 18.3

As a light rare earth element, La element is primarily selected microalloying element in aging strengthened copper alloy. In this study, the La added Cu-Ni-Si alloy is studied for clarifying structure and type of the second phase formed by La element and other elements. The Cu-Ni-Si alloy with addition of La exhibits different texture types and stronger interaction between Ni2Si phase and nano-twins compared to the alloy without La element. Such difference contributes the excellent resistance to over-aging of the La contained Cu-Ni-Si alloy. Meanwhile, the structure of the La-rich phase was explored using a transmission electron microscope with multiple probes and a fast imageable X-ray energy spectrum analysis probe as well as first-principle calculations. The addition of La element in the alloy formed two kinds of rich La phases, LaNi9Si4 and LaNi2Si2, which both show incoherent relationship with the matrix. Specially, a new kind of core-shell structure is found with shell of LaNi9Si4 and core of LaNi2Si2. This characteristic can be used as a dispersion strengthening phase in the subsequent design of Cu-Ni-Si alloys, providing a new idea for the research and development of new high-performance Cu-Ni-Si alloys.

An unexpected increase in the electrical conductivity of Cu-Cr-Zr alloy was identified during solid solution treatment, with the conductivity rising from the typical 42.11 % IACS to as high as 88.95 % IACS. Such a significant enhancement in conductivity is driven by oxygen diffusion at 950 °C, where oxygen primarily reacts with dissolved Cr in the matrix, not with primary Cr phases. Specifically, oxygen-driven dissolution of primary Cr phases forms a ring-like structure that further promotes reactions. These reactions result in formation of nano-sized Cr₂O₃ precipitates, thereby contributing to the improved conductivity. These findings suggest a potential method for optimizing copper alloys' microstructure and properties by controlling oxygen content.

Little is known about the mechanical property and formability of CZ1 zirconium alloy sheet. In this study, tensile tests of CZ1 sheet were carried out along rolling direction (RD), diagonal direction (DD) and transverse direction (TD). Nakazima tests were conducted to construct the forming limit diagram (FLD) for CZ1 sheet. Three anisotropic yield criteria including Hill48, Barlat89 and BBC2003 were chosen to calibrate the anisotropic coefficients in order to compare the accuracy for anisotropy description. The classical Marciniak-Kuczynski (M-K) model and different yield criteria are applied to predict the forming limit strains theoretically. After comparison, BBC2003+M-K model predicted FLD is in good agreement with the experimental result. Then the effects of material parameters including hardening exponents (n value) and Lankford coefficients (r-values) on the FLD are analyzed with this approach. Furthermore, the relationship between material parameters and formability can be unveiled aiming at providing an optimized direction for formability.

The Zr-1.0Sn-1.0Nb-0.1Fe alloy sheet with a typical double-peak basal texture was rolled up to 70 % thickness reductions at room temperature to follow its textural evolution. An unusual weakened basal texture under increasing rolling strain is found for cold rolled Zr alloy sheets. Specifically, basal pole is changing from transverse direction (TD) to normal direction (ND) resulting in a stronger basal texture under small deformation amount. For heavy deformation, the maxima of texture components spread from ND to TD. This spreading of the texture change is primarily related to a certain amount activation of pyramidal (c + a) slip, which inhibited the formation of basal texture. In-grain misorientation axes analysis and visco-plastic self-consistent simulation jointly suggested that the distinctive tendency of texture evolution is mainly derived from the competition between basal (a) slip and pyramidal (c + a) slip.

This study focuses on the key failure issues of rolls in the three-roll planetary rolling process. Firstly, through the analysis of failure morphology, it is inferred that the main failure mechanisms are the initiation and propagation of thermal fatigue cracks and severe friction and wear. On this basis, the thermal fatigue and friction wear tests of the roll material were designed and carried out. The research results show that the failure behavior of the rolls is jointly dominated by the synergistic effects of thermal fatigue and friction wear. By systematically analyzing the evolution law of cracks, a thermal fatigue damage model with crack length and crack area as core parameters was established, thereby effectively evaluating the crack propagation behavior of rolls. Further research indicates that coating the surface of the rolls with diamond-like carbon (DLC) coatings can significantly enhance their thermal fatigue resistance and friction and wear performance, providing theoretical support and experimental basis for greatly extending the service life of the rolls.

To solve the difficulty of forming complex parts of aluminium alloy, a method was proposed using local hardening by laser heat treatment (LHT) to improve the formability of the Al alloy sheet. In order to explore the influence of laser local hardening on deep drawing forming performance, the temperature field of laser treatment was simulated based on the measured data, and a sheet model coupled with mechanical property gradient was established. In addition, the mechanism of the improvement of material formability by the change of constitutive parameters was revealed by the combination of simulation and experiment. The results show that laser scanning can generate a stable gradient temperature field with little influence on the surrounding area. Furthermore, the multi-pass scanning allows for the design of property gradient differential sheets with varying ranges. It is proved that the LHT can effectively improve the plastic strength and the local hardening ability of Al alloy. The results of deep drawing simulations and tests show that the LHT mainly affects the forming ability of differential aluminium alloy sheets by regulating the gradient distribution of strain hardening exponent n and strain hardening coefficient k. The gradient decreasing distribution of n value from the heat treatment center to the surrounding area can not only improve the forming ability of the core area, but also alleviate the strain concentration in the periphery, so as to achieve a more uniform strain distribution in the large deformation zone. The gradient distribution of k can change the position and order of the yield behavior of the plate, and then change the material flow sequence, thus slowing down the material flow at the bottom fillet with higher k value and reducing the tendency of thinning and cracking. In particular, it is found that the gradient distribution of k value is the dominant factor to improve the forming ability of poor aluminium alloy sheet. When the gradient of k value distribution between the laser strengthening area and the surrounding material reaches the critical value, the fracture position of the deep drawing part will shift, which greatly delays the occurrence of necking and cracking processes and improves the overall forming ability of the sheet.

This study systematically examines how microalloying with La influences the hot deformation behavior and microstructure evolution of Cu-Ti alloys. Isothermal compression tests on Cu-3Ti and Cu-3Ti-0.1La alloys were performed using a Gleeble simulator at 500-800 °C and strain rates of 0.01-10 s−1. True stress–strain curves were obtained and used to establish a Zener–Hollomon constitutive equation. Results indicate that La addition refines grains, promotes Ti-rich phase precipitation, lowers hot deformation activation energy from 574.1 to 551.2 kJ/mol, and improves hot workability and deformation stability. A backpropagation neural network (BPNN) model was also developed to predict flow stress. Comparison between the Levenberg–Marquardt and Bayesian regularization (BR) algorithms shows that a single-hidden-layer BPNN using BR achieves the highest accuracy (R = 0.99985), avoids overfitting, and offers superior generalization and reliability. This work provides theoretical support for hot processing design of high-performance Cu-Ti alloys and validates the effectiveness of machine learning in materials constitutive modeling.

The structural integrity of welded joints is critical to the safety and long-term durability of aluminum alloy components in automotive and aerospace applications, where fatigue failure frequently initiates at localized stress concentrations. This study investigates the fatigue performance of representative welding configurations in 6061 aluminum alloy. The fracture mechanisms and underlying microstructural evolution, particularly dislocation behavior, in the welded joints were characterized to elucidate the failure origins. Additionally, this study proposes a high-precision fatigue life prediction method for welded components, leveraging finite element numerical simulations, empirical fatigue performance data of 6061 aluminum alloy base material, and key correction parameters from the Forschungskuratorium Maschinenbau guideline. The method establishes fatigue life predictions based on stress characteristics at critical locations—specifically, those corresponding to characteristic points on the fatigue S-N curve. While validated for aluminum alloy welded joints, the approach is broadly applicable to engineering components, offering a novel and robust framework for fatigue performance assessment.

This study systematically investigated the influence of Te content (0.18, 0.4, and 0.57 wt%) and aging treatment on the mechanical strength and electrical conductivity of Cu-xTe-0.3Cr alloys (x = 0.18, 0.4, and 0.57 wt%). After controllled aging at 300 degrees C-550 degrees C for 1 h, the alloys developed a tailored multiscale microstructure consisting of nanoscale Cr precipitates, microscale Cr phases, bar-shaped secondary Cu2Te dispersoids, and dense dislocation networks. This hierarchical microstructure integrates precipitates across nanometer to micrometer scales, dislocation configurations, and grain status, collectively governing the alloy's strength-conductivity synergy. The results revealed that increasing Te content significantly promoted the formation of Cu2Te precipitates, with the quantity and size of these phases exhibiting a strong dependence on Te content. The aging process further induced dense dislocation networks and refined the precipitates, thereby facilitating synergistic strengthening mechanisms. Peak performance was achieved in the Cu-0.4Te-0.3Cr alloy after aged at 500 degrees C for 1 h, which attained a Vickers hardness of HV 147 and an electrical conductivity of 85.58% IACS. These enhancements are attributed to the synergistic effects of precipitation strengthening (from coherent nanoscale Cr precipitates and Cu2Te dispersoids) and dislocation pinning. This combination effectively impedes dislocation motion while reducing lattice distortion to maintain electron transport efficiency. This work provides a strategic framework for designing high-performance Cu-Te-Cr alloys with optimized strength-conductivity synergy via tailored multiscale microstructures, thereby advancing their application potential in demanding scenarios such as high-current connectors for next-generation energy technologies.

Bipolar plate is one of the most important components of proton exchange membrane fuel cells, which has the basic functions of conducting electricity, supporting membrane electrode assemblies, uniformly distributing and isolating reactant gas, circulating coolant, and rapid heat dissipation. In this article, taking the micro runner flexible forming process of 316L stainless steel sheet as the research object, the influence of process parameters on the forming quality of micro flow runners is analyzed. The results show that an increase of the equipment pressure and a decrease of the soft film hardness are conducive to the improvement of the forming depth of a bipolar plate, while the holding time has a minor effect on the forming depth. Under the same loading conditions, the forming depth of a 0.1 mm thick sheet is smaller than that of a 0.075 mm sheet. An increase of the grain size reduces the difficulty of forming, and the larger the grain size, the larger the forming height and runner filling rate. However, with an increase of the grain size, the surface roughness of the bipolar plate increases and the wall thickness of some parts of the runner becomes uneven.

Zircaloy-4 (Zr-4) sheets used in fuel assembly structural parts are subjected to high temperatures, stresses, corrosive environments, and radiation. Due to the poor formability of Zr-4, cracks usually occur during the fabrication of spacer grids at room temperature. In this research, annealed Zr-4 sheets with two distinct initial textures were studied during stamping. Experimental results showed that the sheet with higher normal Kearns factors exhibited weaker formability, leading to cracking at the punch radius under the same punching depth. Electron backscatter diffraction (EBSD) observations revealed discrepancies in texture evolution under different strain paths during plastic deformation. A multi-scale simulation was conducted to elucidate the deformation mechanisms. Modeling accuracy was validated by comparing crack locations, thickness distributions, and post-deformation textures with experimental results. The contribution of slip and twinning to crack formation was quantified. The simulation indicated that Zr-4 sheets with weaker textures exhibited better deformation compatibility, primarily due to enhanced activation of prismatic slip, whereas sheets with stronger textures showed dominant basal slip activity, which promoted cracking.

Bipolar plate is one of the most important components of proton exchange membrane fuel cells. In this paper, taking the micro channel flexible forming process of 316L stainless steel sheet as the research object, the influence of process parameters on the forming quality of micro flow channel is analysed, so as to provide guidance for the flexible forming of bipolar plate. The effect of equipment pressure and hardness of soft film on micro flow channel forming has been studied. In particular, the effect of different grain sizes on the forming quality was studied. The results show that the increase of equipment pressure and the decrease of soft film hardness are conducive to the improvement of the forming depth of bipolar plate. Under the same conditions, the increase of grain size reduces the difficulty of forming, and the larger the grain size, the larger the forming height and channel filling rate. However, with the increase of grain size, the surface roughness of the bipolar plate increases and the wall thickness of some parts of the runner is uneven.

The rapid advancements in electronics, electric vehicles, and green technologies have imposed increasingly stringent demands on copper-based materials. These requirements include high thermal and electricity conductivity, corrosion resistance, and strength properties at both room temperature and high temperatures. Rare-earth elements are excellent microalloying agents due to their typical metallic properties and highly active chemical characteristics; these properties and characteristics enable them to react with almost all elements except noble gases. The addition of rare-earth elements to copper and copper alloys can have several beneficial effects, such as impurity removal, purification, enhancement of the metallographic structure, and improved corrosion resistance. These effects can also raise the heat treatment temperature and enhance plastic processing, thereby further improving the overall properties of copper alloys. This review examines the influence of rare-earth elements (REEs) on copper and its alloys, along with their diverse industrial applications. It was found that elements such as La, Ce, Y, and Nd are commonly added to enhance properties like electrical conductivity, strength, corrosion resistance, purity, and hot workability in alloys such as pure copper, Cu-Ni-Si, Cu-Cr-Zr, and Cu-Fe-P. The review will lay a foundation and provide novel method for the development of advanced copper alloy.

The presence of a particular type of white powder has emerged as a significant challenge in the horizontal continuous casting process of copper. This white powder leads to the blockage of the graphite crystallizer, resulting in a functional failure that adversely affects the mold's lifespan, increases production costs, and reduces overall efficiency. The issue has posed significant challenges for engineers due to its complex and unclear formation mechanism. This investigation employed various experimental characterization methods to analyze the composition, element distribution, phase properties, and other relevant factors of the white powder. Meanwhile, a high- temperature experiment was also designed to examine the potential reactions between copper oxide (Cu2O) and the furnace lining (3Al2O3 & sdot;2SiO2). It is found that the main component of the white powder blocking the inlet hole of the graphite mold is SiO2, which is traced back to the furnace lining. Under high temperatures, oxygen reacts with liquid copper to form Cu2O. Subsequently, this Cu2O reacts with Al2O3 in the furnace lining to produce CuAlO2. Meanwhile, SiO2 becomes isolated as Al2O3 is deprived. The resultant SiO2 accumulates at the inlet hole of the graphite mold due to rapid cooling. The accumulated SiO2 in the form of white powder blocks the inlet hole of the graphite mold, leading to functional failure of the graphite mold. To address this issue, several improvement measures are proposed including drying the raw and protective material, enhancing the sealing of the furnace, and reducing the holding time.