Effect of MGZN2 addition on the sintering density, microstructure and hardness of aluminum alloys prepared by powder metallurgy method

Abstract

In this study, the aluminum alloys with different MgZn2 contents were prepared using the powder metallurgy method. The effect of the MgZn2 contents on the sintering density, po-rosity, microstructure and microhardness was investigated using optical microscopy, scan-ning electron microscopy (SEM), X-ray diffraction, and Vickers microhardness. The function mechanism of the intermetallic compounds formed as a result of MgZn2 addition was ana-lyzed. The results revealed that the highest sintering relative density (95.1%), lowest porosity volume fraction (4.81%), and highest hardness (112.4 HV) were observed with the 5% addi-tion of MgZn2 contents. The XRD results show that the microstructure of the bare sample (Al) is mainly composed alpha-Al phase, while, with the addition of MgZn2, the microstructure turned to have alpha-Al phase and some intermetallic compounds of Al5Mg11Zn4 and AlMg4Zn11. These intermetallic compounds were formed with higher density at the grain boundaries as white precipitates.