Microstructure, mechanical properties and strengthening mechanisms of AlCu5MnCdVA aluminum alloy fabricated by selective laser melting

Selective laser melting (SLM) was employed to fabricate the aluminum alloy AlCu5MnCdVA in this work. The microstructure, mechanical behavior, anisotropy, and strengthening mechanisms were investigated. The results show that the main phases consist of alpha-Al and Al2Cu. In addition, the supersaturated solid solution with fine columnar grain, high dislocation density and weak texture has been obtained. There is little difference in mechanical properties when the scanning velocity changes if dense samples are obtained. The yield strength, the ultimate strength (UTS) and the elongation are 145.5-157.6 MPa, 309.1-319.7 MPa, 11.44%-14.34%, respectively. The anisotropy is weak, which results from the weak texture. The horizontal specimens show a little higher yield strength and lower elongation. The UTSs of the samples are nearly the same. The strongest anisotropy results from the lowest scanning velocity. The solid solution strengthening, grain boundary strengthening, dislocation strengthening, precipitate and dispersoid strengthening contribute to the strength of the specimens. The quantitative analyses show that all the four strengthening mechanisms dominant in the SLMed AlCu5MnCdVA alloys.