The low carbon low alloyed (LCLA) dual-phase (DP) steel with ultrahigh strength-ductility synergy has enormous potential applications in the automotive industry. In this study, a novel strategy was proposed to pursue such high performance of LCLA steel by coupling the quenching and partitioning (Q&P) treatment with an intercritical annealing (IA) process. The newly developed hetero-structured LCLA DP steel exhibits superior mechanical properties with a remarkable increase in uniform elongation by nearly 2 times (above 7 %) compared with the conventional DP steel, yet maintaining ultrahigh yield strength (about 1350 MPa) and ultimate tensile strength (about 1630 MPa). The promising heterogeneous microstructure of the Q&P + IA steel exhibits coarse ferrite grains tightly constrained by the surrounding fine-grain domains. The multi-level heterogeneity in the designed microstructure is attributed to diverse phases and a bimodal grain size distribution. This configuration contributes to the strong hetero-deformation-induced (HDI) strengthening. Meanwhile, the significant dislocation accumulation facilitates dislocation forest strengthening during deformation. The synergistic effect of both strengthening results in enhanced strain hardening in the DP steel. This study may provide a new economical route to produce inexpensive ultrahigh-strength DP steel with considerable ductility.

Three-dimensional (3D) nanoporous nitrogen-doped graphene is an ideal candidate for solar steam generation. However, the outermost dense layer formed during high-temperature thermal chemical vapor deposition (CVD) severely blocks water transport and steam escape. In this work, a technique of femtosecond laser opening hierarchical lamination (FLOHL) enabling hierarchical micro-nano hybrid scissoring of graphene is presented for its structural and performance upgrades. FLOHL not only allows noncontact rapidly hierarchical opening of the blocked layer but also enables opening lamination of close thin-wall graphene into suspended sheets, while maintaining a robust connection with the framework facilitating stable repetitive use for water evaporation. After FLOHL, solar absorption, heat localization, and interfacial wetting are all dramatically enhanced, increasing water evaporation rates from 1.58/1.56 to 1.79/1.77 kg m-2 h-1 for two prototypes under 1 sun irradiation and conversion efficiency from ∼80% to ∼90%, making them better than many solar evaporators built with graphene and its derivatives, including laser-induced graphene.

The pursuit of alloys that integrate high strength and substantial plasticity persists across various industries. Nevertheless, alloys engineered for elevated strength commonly manifest unsustainable work hardening, ultimately leading to a decline in plasticity. Dual-or even multi-phase systems offer vast potential for novel microstructural engineering aimed at harmonizing these inversely related property requirements. Here, heterogeneous lamellar structure consisting of alternating austenite and ferrite lamellae is explored to decouple and leverage the distinct roles of individual phases in a dual-phase system. This phase-specific tailoring strategy meticulously manipulates intra-phase microstructure, and tunes the lamella thickness to promote both high initial strength and prolonged work hardening. The significantly enhanced strength benefits from pre-existing defects, interfaces strengthening and quasi isostrain deformation mode while high plasticity originates from relatively uniform strain partitioning between phases across a wide strain range achieved through exploiting various hardening components. For austenite, prolonged work hardening is achieved by sequential utilization of dislocation hardening followed by martensitic transformation hardening. Moreover, the martensite laths in favorable configuration along with the retained austenite contribute to retarding cracking. For ferrite, wide-range work hardening is ensured by expanding the potential for dislocation activities which lowers initial density and raises peak density through reducing the space in the thickness dimension. Such innovation elevates the traditionally inferior work-hardening capability of high-strength BCC structure to an exceptional level. The resultant alloy, while boosting nearly twice the yield strength of its conventional counterpart, exhibits a total elongation of 45 %. This strategy holds potential for broad application across dual-and multi-phase systems and proposes a new avenue for enhancing plasticity in high-strength lamellar-structured alloys.

Developing high-temperature metallic glass thin films (MGTFs) with excellent combination properties is crucial for extending the practical applications of metallic glasses. A high-temperature multicomponent Mo-based MGTF with tunable microstructure prepared by single-target magnetron sputtering was presented in this study. Corresponding mechanical behaviors and thermal stability of MGTFs related to microstructure are systemically explored. By adjusting deposition parameters (pressure and power), the microstructure of as-deposited MGTFs can be altered from the dense homogeneous type to the loose nanoglass type. Such structure evolution can be explained by the competition between the surface diffusion and geometric shadowing effect. MGTFs with dense microstructure possess smaller surface roughness, higher hardness, higher Young's modulus, and better wear resistance. Moreover, they also possess higher thermal stability where the fully amorphous structure and smooth surface can be well maintained after annealing at 1123 K for 30 min. By contrast, the MGTF with nanoglass microstructure shows inferior mechanical properties and thermal stability due to plentiful loose interface regions, providing abundant free volumes during deformation and acting as favorable crystal nucleation sites during annealing. The correlation between the microstructure and properties of as-deposited MGTFs is clarified with the universal scaling law of glasses. The annealing treatment distinctly increases the hardness and Young's modulus of MGTFs. Meanwhile, after annealing, pop-in behaviors occur in the as-annealed MGTFs with dense microstructure but not in the as-annealed MGTF with nanoglass microstructure during the nanoindentation. These phenomena can be rationalized by the annihilation of free volumes during annealing and the evolution of the dynamical variable, shear transition zone, for the plastic deformation in MGTFs.

Thin film metallic glass (TFMG) has demonstrated significant potential for applications in the semiconductor industry. In this work, fully amorphous Mo-Co-B thin films with a smooth surface and dense microstructure were prepared through magnetron sputtering. The thermal stability and diffusion barrier performance of the Mo-based TFMG were evaluated through vacuum annealing at temperatures ranging from 300 to 800 degrees C for 30 min. Nanoindentation tests were conducted to investigate the evolution of mechanical properties with annealing for the Mo-based thin film. When subjected to annealing at temperatures below 700 degrees C, the Mo-based thin film retained its fully amorphous structure. It displayed enhanced hardness and Young's modulus due to the annihilation of free volume with annealing. Increasing the annealing temperature to 700 degrees C and 800 degrees C resulted in surface oxidation and crystallization of the Mo-based TFMG, respectively, leading to a continuous decline in its mechanical properties. When employed as the diffusion barrier between Cu and Si, the Mo-based barrier layer effectively blocked the diffusion of Cu atoms through the barrier at temperatures below 800 degrees C. The failure of the barrier occurred at 800 degrees C due to the crystallization of the amorphous phase. Such excellent diffusion barrier performance of the thermally stable Mo-Co-B TFMG makes it a promising candidate as the barrier material in Cu metallization.

Restrained by the strength-ductility tradeoff, it is still challenging to develop advanced high-strength low carbon low alloy (LCLA) steels with superior strength-ductility combinations and cost-effectiveness to satisfy industry demands. In this study, an innovative 2-cyclic quenching and partitioning (Q&P) heat treatment was developed to produce a novel LCLA steel with the optimized microstructure, in which a bimodal grain size distribution across various constituent phases was achieved. Tensile test results show that the 2-cyclic Q&P LCLA steel exhibits excellent mechanical properties with a uniform elongation, close to 18%, nearly triple that of conventional Q&P LCLA steel while maintaining a tensile strength above 1 GPa. To reveal the underlying mechanisms of such exceptional strength-elongation synergy, the detailed deformation behaviors of the developed LCLA steel were characterized while the evolution of hetero-deformation-induced (HDI) stress and effective stress was investigated from the perspective of the dislocation model. It is indicated that, with increasing strain, the heterogeneous structures promote strong strain partitioning which leads to extensive geometrically necessary dislocations (GNDs) pile-ups at hetero-interface and persistently strong HDI strengthening effect, and produce the coordinated deformation among constituent phases to realize dislocation forest strengthening, collectively contributing to the enhanced work hardening capacity and hence overcoming the strength-ductility tradeoff. This study provides a new processing strategy for developing strong and ductile LCLA steels.

2-Methoxyethanol (2ME), as a more environmentally friendly solvent with a lower boiling point compared to dimethylformamide, is ideal for the fabrication of perovskite solar cells (PSCs). However, when 2ME is used for antisolvent-free deposition of perovskite films, an uncontrolled nucleation process and an easy phase transition to the delta-phase often occur. Herein, an ultrafast nucleation process is developed using methylamine chloride (MACl) and n-butylammonium chloride (BACl) as dual additives in 2ME without further solvent addition. While MACl can rapidly induce MACl-based nuclei to initiate the nucleation process for formamidinium lead iodide (FAPbI(3)), the addition of BACl to the precursor with MACl can further increase the nucleation rate and density of nuclei, and bypass the transition from delta- to alpha-phase during crystal growth to obtain a highly crystalline and pinhole-free perovskite film. As a result, the FAPbI(3) PSCs achieve a power conversion efficiency (PCE) of 23.6%. This work provides a new inspiration for controlling the crystal quality of perovskite thin films via nucleation rate suitable for upscaling.

NiCoCr, as a model medium entropy alloy has been investigated extensively in the past decades. To further improve the mechanical properties of NiCoCr, there are mainly two methods. One is thermal-mechanical treatment. The other is to add some proper alloying elements to introduce second phase to fabricate the precipitate strengthening medium entropy alloys. Inspired by this, a superior medium entropy alloy (NiCoCr)(95)V-5 was successfully fabricated by cold rolling and subsequent two-step annealing in this study. The strength and plasticity product exceeds 86 GPa center dot% that is comparable to the currently reported high-performance medium and high entropy alloys. The microstructure characterizations indicate that the dislocation slip and interacting with high density nanoscale precipitates, the initiation of primary and secondary deformation twinning which further segmenting the grains are the main reasons for such high properties. This work enriches the design and development of medium and high entropy alloys with high-strength and high plasticity.

Green-solvent-processed perovskite solar cells (PSCs) have reached an efficiency of 20%, showing great promise in safe industrial production. However, the nucleation process in green-solvent-based deposition is rarely optimized, resulting in randomized crystallization and much lowered reported efficiencies. Herein, a nanostructured tin oxide nanorods (SnO2-NRs) substrate is utilized to prepare a high-quality formamidinium (FA)-based perovskite film processed from a green solvent of triethyl phosphate (TEP) with a low toxic antisolvent of dibutyl ether (DEE). Compared with SnO2 nanoparticles, the oriented SnO2-NRs can accelerate the formation of heterogeneous nucleation sites and retard the crystal growth process of the perovskite film, resulting in a high-quality perovskite film with uniform grain growth. Furthermore, a chlorine-terminated bifunctional supramolecule (Cl-BSM) is introduced to passivate the increasing interfacial defects due to the vast contact area in SnO2-NRs. Correspondingly, the substrate design of SnO2-NRs with Cl-BSM increases the power conversion efficiency (PCE) of green-solvent-processed PSCs to 22.42% with an open-circuit voltage improvement from 1.02 to 1.12 V, which can be attributed to the uniform grain growth and reduced carrier recombination at the SnO2-NRs/perovskite interface. More importantly, the photo and humidity stabilities of the unencapsulated device for up to 500 and 1000 hours are also achieved with negligible interfacial delamination after aging. This work provides a new perspective on the future industrial scale production of PSCs using environment-friendly solvents with compatible substrate design.

The performance and reliability of integrated circuits depend on the mechanical and electrical properties of the interfaces between thin films and the silicon wafer. One of the essential properties of the interface is its adhesion energy. However, conventional adhesion characterization methods could be further improved, especially in providing repeatable and reliable measurements. In this paper, we measured the adhesive strength of the interface between tungsten thin films and silicon wafers in micro-sized specimens using a direct push-to-pull device built into a nano-indenter. A scratch method with a transparent theoretical model was applied to quantify the same interfaces' adhesive strength, adhesion energy, and fracture resistance. Microscopic and mechanical analysis clarified the physical origin of thin film delamination. The current method precisely quantified the interfaces' adhesive strength and fracture resistance. This method is promising for sub-micron thin film designs in the semiconductor industry with its superior repeatability, reliability, and ease of operation.

The alloy design for high-nitrogen duplex stainless steels (DSSs) has been received ascendant attentions due to their excellent strength, ductility and anticorrosion. However, the yield ratios of these steels are usually low and cannot meet the requirement of structural parts. In this work, a DSS 2202 with fine austenite grains and bimodal ferrite structure was obtained through ingenious heat treatment and rolling process and the yield strength (YS) increased from 416.5 to 716.4 MPa while the total elongation still maintained at high level of 45.8%. Furthermore, the transformation-induced plasticity (TRIP) effect was suppressed during the whole tensile test. Based on the detailed microstructure characterization, the deformation mechanism of this DSS was discussed and a novel strengthening method was proposed, that is, the unusually rapid dislocation proliferation mechanism in coarse ferrite was triggered and its dislocation density reaches to 1.3326 x 10(14) m(-2) after deformation which is equivalent to that of austenite (1.5229 x10(14) m(-2)). This work provides a new way for the material selection of some structural components with the demands of high yield ratio and high corrosion resistance. (c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The mechanical properties and plastic deformation of a Cu(55.4)Zr(35.2)Al(7.5)Y(1.9 )nanoporous metallic glass (MG) have been studied using depth-sensing nanoindentation combined with electron microscopy characterization. The nanoporous MG exhibits an initial relative density of 50.9% and a bicontinuous structure with 20.84 +/- 1.49 nm-diameter interconnecting ligaments. It is brittle in tension, whereas it has significant homogeneous plasticity under compression. It has a hardness of 0.67 +/- 0.06 GPa and Young's modulus of 14.72 +/- 0.74 GPa from nanoindentation. While under tensile and compression, it has a yield strength of 0.22 to 0.23 GPa and an effective modulus of 10.37 +/- 0.99 GPa. The discrepancy between the moduli is caused by irreversible shear transformation zone (STZ) plasticity that takes place well ahead of the yield point. The deformation in the nanoporous MG begins with both elastic and plastic bending in ligaments and transfers to plastic uniaxial deformation in ligaments at a critical strain near 0.03, at which a significant change in stiffness is observed. The yielding stress follows the universal scaling law predicted by the critical-like behavior in glassy systems. The strength to modulus ratio is well maintained in this nanoporous MG and is higher than the porous crystalline alloys. Our experimental study clarifies the fundamental failure mechanism and deformation behavior in nanoporous MGs.

The microstructure and mechanical property of Ti-14Al-10Nb alloy as casted condition which carried out at heat treatment temperatures were studied. Through the X-ray diffraction and microstructure observed, it can be indicated that the microstructure of Ti-14Al-10Nb alloys was composed of α2 phase and β phase in cast condition. During the heat treatment process, the content of α2 phase decreased and accompanied by the thickness of α2 phase reduced as the temperature rose. As casted condition, the compression strength of Ti-14Al-10Nb alloy was 1320 MPa, and compressive strain was 0.161. The element Al and Nb solubilized in β phase leading to the solution strengthening strengthened during heat treatment process, so the plastic property of Ti-14Al-10Nb alloy was deteriorated. While alloy carried out at 900℃ for 60 minutes, the compressive strain was only 0.0236. Meamwhile, the trend of compression strength was first falling then rising as a result of comprehensive effect of phase strengthening and solution strengthening.

A family of Fe-70(ZrNbTi)(10)B-20 bulk metallic glasses (BMGs) were developed through the stepwise substitution of Nb and Ti for non-major solvent element Zr. The glass-forming ability (GFA), magnetic and mechanical properties of Fe70Zr10B20, Fe70Zr6Nb4B20 and Fe70Zr4Nb4Ti2B20 metallic glasses were studied to explore the influence of minor similar solvent element substitution. With the substitution of 4 at.% Nb for Zr, the critical diameter of Fe70Zr6Nb4B20 BMG increases to 1 mm while the saturation magnetization (M-s) decreases slightly. After the further substitution of 2 at.% Ti, the resulting BMG exhibits higher GFA and lower M-s. The enhanced GFA and decreased M-s are attributed to the more solute-solute avoidance and smaller average magnetic moments of the resulting bulk metallic glass, respectively. In addition, the analysis of charge density distribution reveals the origin of high fracture strength and microhardness of Fe70Zr4Nb4Ti2B20 BMG.

The influence of the substitution of metalloid element P for Fe in Fe-P-C-B amorphous system on phase constituent, thermal properties, tensile mechanical properties and bending ductility were evaluated. The transition behavior from brittleness to ductility for the amorphous ribbons can be controlled through the alloy design. Moreover, the atomic and electronic structures of the typical Fe-P-C-B metallic glasses were simulated by the ab–initio calculations. Combining with experimental and theoretical results, it provides a possible understanding of the brittle-ductile transition caused by the chemical element tailoring in Fe-P-C-B metallic glasses.