Microstructure and properties of high strength Al-Fe-Cu-Si-Zn alloy (AA8079) produced by mechanical alloying and powder metallurgy

摘要

The intent of this work is to synthesize Al-Fe-Cu-Si-Zn alloy (AA8079) at different milling hours, i.e. 1, 10, 20, 30 and 40 h, by mechanical aloying (MA). X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis was carried out for the milled powders. From the SEM images, a significant change in the size and shape of the particle was observed while the milling time was extended from 1 to 40 h. The effect of milling time on properties such as density, hardness and compressive strength was analyzed. After mechanical alloying, the powders were compacted at three different compaction pressures (500 MPa, 550 MPa & 600 MPa) and sintered in a furnace at different temperatures (500 degrees C, 550 degrees & 600 degrees C) under a controlled atmosphere for 1 h, 2 h and 3 h. An extreme Vickers hardness of 815 MPa and compressive strength of 327 MPa were achieved for 40 h milled powders compacted at 600 MPa, sintered at a temperature of 600 degrees C for a period of 3 h. A optical micro-scope (OM) and SEM analysis were conducted for the sintered AA8079 samples to study the effect of milling time and PM parameters on the microstructure.