Effect of low-temperature annealing on the mechanical anisotropy and microstructure of Selective Laser Melting (SLM) AlSi7Mg alloy
Year: 2026
Type: article
Abstract: This study investigates the microstructural evolution and mechanical anisotropy of Selective Laser Melting (SLM) AlSi7Mg alloy before and after low-temperature annealing. The effect of heat treatment on the anisotropic behavior of the material was examined through tensile tests, SEM, quasi in-situ Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM). The results reveal that the SLM AlSi7Mg alloy exhibit notable mechanical anisotropy, particularly in ductility, with the XY orientation showing higher strength and the Z orientation showing better elongation. After low-temperature annealing (170°C/4h), the anisotropy in both strength and ductility was reduced, with improvements in mechanical performance observed in both orientations. The anisotropic tensile elongation was mainly caused by differences in crack propagation behavior, with cracks propagating along melt pool boundaries in the Z samples and along cellular boundaries in the XY samples. The Z samples exhibited a higher work-hardening rate due to the activation of additional slip systems, facilitating dislocation motion. Low-temperature annealing promoted the formation of deformation twins of Si, coarsening of Si precipitates, and the reduction of stacking faults, which enhanced dislocation mobility and improved overall mechanical properties. This work highlights the potential of low-temperature annealing in refining microstructure and optimizing mechanical properties for SLM AlSi7Mg alloy, particularly in applications requiring balanced strength and ductility.
Institution: Nanjing Tech University
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,640
OpenAlex ID: W7119054015