Selective Laser Melting of Al-Cu-Mn-Mg Alloys: Processing and Mechanical Properties

Abstract

Al-Cu-Mn-Mg alloys containing Zr were produced via selective laser melting (SLM). The processing parameters were analyzed via an orthogonal experiment, and the microstructure and mechanical properties of the specimens were investigated. The results showed that the laser power and scanning speed were the main factors affecting the density and hardness of the specimens. The optimal parameters for the SLM processing of Al-Cu-Mn-Mg alloy were a laser power of 300 W, scanning speed of 1100 mm/s, and hatch spacing of 0.12 mm. The microstructure of the specimen was made of fine equiaxed grains and columnar grains, and Al2Cu precipitates were found in the as-printed alloy. The alloy was isotropic, and the hardness was around 100 HV. The tensile and yield strength of the alloy were 361 MPa and 266 MPa, and the elongation was 5.4%. The superior mechanical properties can be attributed to the synergy effect of the strengthening of the grain boundary, solid solution, and precipitation.