Investigation of a New Type of Aluminum–magnesium Alloy With Bismuth Additions Subjected To Thermomechanical Heat Treatment

Abstract

In this study, the changes in microstructure, hardness, corrosion and wear properties of Al-Mg with 3% Mg content and new type Al-Mg-Bi alloys with 1.3% Bi addition were investigated with the application of thermomechanical process on the aging heat treatment characteristics. As a result of the applied thermomechanical process, a finer grained structure was obtained and a higher hardness value was achieved compared to the casting alloys. Bright phases in SEM micrographs were detected as (rod-shaped) intermetallic (Al6Mn) particles in TEM analyses. Additionally, it was determined that the independent dark particles in the Al matrix were Mg2Si phases. Both alloys showed evidence of the Al3Mg2 phase. However, corrosion tests have shown that the Al-Mg-Bi1.3 alloys with the addition of bismuth have higher corrosion resistance than the Al-Mg alloys. The Al-Mg-Bi1.3 alloys also exhibited improved wear resistance in dry and corrosive wear tests. While the wear of the investigated alloys in a dry environment is associated with an improvement in hardness, wear resistance in corrosive media is improved by the addition of Bi, which reduces the formation of certain phases. Graphical Abstract: [Figure not available: see fulltext.] © 2023, American Foundry Society.