Heat Treatment of AZ91-5wt.%Sn Magnesium Alloy

Abstract

The microstructure, electrical conductivity and hardness variation of an AZ91-5wt%Sn Mg alloy sample during a solid-solution and aging heat treatment were instigated by optical microscopy, scanning electron microscopy, X-ray diffraction and by Rockwell hardness techniques in this study. The XRD result shows that the main phases in the as-casted alloy are α -Mg, Mg 17 Al 12 and Mg 2 Sn. From the SEM images of the AZ91-5wt%Sn Mg alloy after the solution treatment, the Mg 17 Al 12 phases in the alloy were found to have dissolved into the matrix with an increase in the holding time during the solution treatment, but Mg 2 Sn phases were clearly observable. The highest peak hardness of the AZ91-5wt%Sn Mg alloy is 82HRE at an aging temperature of 200 o C.