Effect of Annealing Temperature on Microstructure and Properties of Selective Laser Melting Alsi10Mg Alloy

The AlSi10Mg alloy was formed by laser selective melting, and annealed at different temperatures (260, 270, 280, 290, 300 ℃). The effect of annealing temperature on the microstructure, phase composition, microhardness and tensile properties of the alloy was studied. The results show that the AlSi10Mg alloy before and after annealing at different temperatures was mainly composed of α-Al, silicon and Mg₂Si phases. before annealing, the AlSi10Mg alloy had fine grains, uniformly distributed network eutectic silicon and uniformly dispersed secondary silicon particles in the aluminum matrix. After annealing and with the increase of annealing temperature, network eutectic silicon had undergone fracture, coarsening and spheroidization, and the number of secondary silicon particles decreased until it almost disappeared. Compared with the alloy before annealing, the lattice distortion of the alloy after annealing decreased. As the annealing temperature increased, the reduction degree also increased. Compared with those of the alloy before annealing, after annealing and with increasing annealing temperature, the microhardness, tensile strength and yield strength of the alloy decreased, while the percentage elongation after fracture increased.