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This study delves into effects of deep cryogenic treatment (DCT) on enhancing the hydrogen embrittlement resistance of CoCrFeMnNi high-entropy alloy fabricated via laser powder-bed-fusion (L-PBF). Comparatively assessing as-print, conventional heat treatment, and DCT, we uncover how nanotwin formation within matrix serves as a critical mechanism to combat adverse effects of hydrogen embrittlement. This work reveals that DCT not only mitigates inherent residual stresses from L-PBF, thereby fostering dislocation redistribution and microstructural stabilization, but also synergizes with high-density dislocation cells. Our findings articulate a nuanced understanding of microstructural evolution in response to post-treatments and consequential enhancement of hydrogen embrittlement resistance. Laser-based additively manufactured CoCrFeMnNi undergoes post heat treatment and deep cryogenic treatment to tailor dislocations and residual stress. The inherent residual stress acts as the driving force for the redistribution of dislocations, leading to the development of a stable microstructure after deep cryogenic treatment. High-density dislocation cells and hydrogen collaborate to lower the local stacking fault energy, triggering gradient nanotwins. Nanotwin-ability effects by deep cryogenic treatment (77 K × 36 h) on the hydrogen embrittlement resistance of CoCrFeMnNi with interior defects are verified. [ABSTRACT FROM AUTHOR]

This study investigates microstructural changes and the presence of multiple stages in strain hardening ratio (SHR) resulting from the sequential occurrence of deformation-induced martensitic transformation (DIMT) during the tensile deformation of an additively manufactured ferrous medium entropy alloy (AMed-FeMEA). The inherent microstructural heterogeneity in AMed-alloys contributes to distinctive deformation mechanisms and instantaneous hardening behavior at varying strain levels. To comprehensively address this phenomenon, a semi-empirical constitutive model is presented that associates multiple stages in SHR with the occurrence rate of DIMT. The model demonstrates its applicability by characterizing tensile deformation of AMed-FeMEA at both room temperature and liquid nitrogen temperature. [ABSTRACT FROM AUTHOR]

Cu–Fe alloys have drawn extensive attraction due to excellent multi-functional properties, including electrical, magnetic, and mechanical properties. However, the immiscible nature of Cu–Fe alloys results in heterogeneous microstructure and unexpected mechanical properties. In this study, a small amount of Zr was added to the cast Cu60Fe40 (wt%) alloy to suppress the liquid–liquid phase separation during solidification of the alloy. The microstructure and mechanical properties of the Zr-free and Zr-containing Cu–Fe alloy were investigated. It is found that the addition of Zr successfully inhibits the heterogeneous microstructural evolution caused by liquid–liquid phase separation, while the FeZr-rich precipitates form in the dual-phase microstructure. The FeZr-rich precipitates affect grain growth of the Zr-containing alloy through the Zener pinning effect, leading to extra grain boundary strengthening and precipitation hardening. The resulting microstructure of the Zr-containing alloy substantially enhances the strength of the alloy with a loss of ductility. The fractured surface reveals that microcracks are formed near the precipitates, which is associated with the reduced elongation of the Zr-containing alloy. [ABSTRACT FROM AUTHOR]

• Thermal battery resilience under high-impact conditions was assessed to sustain continual power supply for electronic devices equipped with artillery projectiles. • Honeycomb buffering devices with different wall thicknesses were adopted to compare their energy-absorption capacities. • Large-scale gas-gun tests and finite element simulations comparing buffering devices revealed distinct deformation patterns influencing impact deceleration. • The thermal battery retrieved from the gas-gun test proved to have reliable impact resilience for the target performance. Modern warfare relies heavily on electronic equipment, necessitating reliable energy sources like thermal batteries. Assessing their impact resilience, a study employed honeycomb-structured Al plates as buffering devices in a large-scale gas gun simulating artillery fire. Comparison between peak curves from gas-gun tests and simulations with varying honeycomb wall thicknesses revealed unique patterns, attributed to the buffering device's deformation-restoration process. Different honeycomb wall thicknesses led to varying deformation behavior and impact deceleration, complicating effective energy absorption assessment. Stepped honeycomb wall designs aimed to balance compression, extending energy absorption and reducing deceleration peaks. Prototype honeycomb buffering devices showed improved energy absorption and reduced deceleration during gas-gun tests. Gas-gun tests highlighted complexities in energy absorption assessment, with designs proposing improved energy absorption and reduced deceleration. The actual gas-gun test launched a projectile equipped with a thermal battery and buffering device, resulting in slight casing deformation, while battery cells remained intact, exceeding the standard discharge time (1 h). [Display omitted] [ABSTRACT FROM AUTHOR]