Microstructure and mechanical properties of （ZrH2+TiH2）/Al-Cu-Mn alloy processed by selective laser melting
XU Xiaopeng 1，2，HUANG Weidong 1，2，QIN Shuaishuai 1，2，HUANG Xu 1，2，HE Dongdong 1，2，
WANG Lu 1，2
（1. Fujian Key Laboratory of Intelligent Machining Technology and Equipment, Fuzhou 350118, China;
2.School of Mechanical and Automotive Engineering, Fujian University of Technology, Fuzhou 350118, China）
Abstract：To eliminate the thermal crack of Al-Cu alloy due to its wide solidification interval and improve its
mechanical strength. The ZrH2+TiH2/Al-Cu-Mn composite powder was prepared by mechanical mixing and used
for selective laser melting. The effects of ZrH2-TiH2 on the microstructure and mechanical properties of Al-Cu-
Mn alloy were studied by means of optical microscope, SEM, EDS, hardness tester and tensile test.The results
show that highest density is obtained when the laser energy density is 120 J/mm3. The addition of ZrH2-TiH2 into
the Al-Cu-Mn alloy effectively promoted the columnar-to-equiaxed transition and grain refinement, the hot cracks
are eliminated after ZrH2-TiH2 addition. Compared to the Al-Cu-Mn alloy, the ZrH2-TiH2 added alloy exhibits increased
properties: the microhardness increases by 16.5%, the ultimate strength reaches 356.5 MPa, and the elongation
is 8.8%. After solution treated at 540 ℃ for 1 h and aged at 185 ℃ for 10 h, the ultimate strength of the
sample is further increased to 460.9 MPa, and the elongation reaches 11.4%. The addition of ZrH2 and TiH2 can effectively eliminate the thermal crack in the forming process of Al-Cu alloy and improve the mechanical
properties of the alloy.
2023, Vol. 33 
