Enhancing the mechanical properties of 6061 aluminum alloy through the synergistic effects of twins, stacking faults, nanograins and lattice distortions

Under ultra-low temperature conditions, wrought aluminum alloys exhibit significant dual enhancement effects of super-hardening and high plasticity. This study focuses on leveraging the improved plasticity of aluminum alloys under ultra-low temperature conditions by selecting the widely used 6061-T6 aluminum alloy in industry as the research subject. Utilizing an ultra-low temperature rolling process, the aim is to further explore and enhance its mechanical properties. The research results indicate that after undergoing ultra-low temperature deformation, the yield strength and tensile strength of the aluminum alloy are both significantly increased, surpassing the levels achievable through conventional deformation processes or traditional heat treatments. To further elucidate the evolution of the material's microstructure during ultra-low temperature deformation, molecular dynamics simulations were conducted. The simulation results reveal the generation of numerous shockley partial dislocations within the aluminum alloy, which serve as crucial carriers of plastic deformation. Transmission electron microscope analysis shows the presence of twins, stacking faults, nanograins, and lattice distortions within the grains. These microstructures, which are difficult to observe under room temperature deformation, collectively contribute to the unique strengthening mechanism of ultra-low temperature deformed aluminum alloys. This paper provides an in-depth investigation of the synergistic strengthening effect of these microstructures in aluminum alloys, offering a theoretical foundation for understanding the mechanical behavior and microstructure evolution of aluminum alloy materials after ultra-low temperature deformation.