Effect of Heat Index on Microstructure and Mechanical Behavior of Friction Stir Processed AZ31

Abstract

Friction stir processing modifies the microstructure and properties of metals through intense plastic deformation. The frictional heat input affects the microstructure evolution and resulting mechanical properties. 2 mm thick commercial AZ31B-H24 Mg alloy was friction stir processed under various process parameter combinations to investigate the effect of heat index on microstructure and properties. Recrystallized grain structure in the nugget region was observed for all processing conditions with decrease in hardness. Results indicate a reduced tensile yield strength and ultimate tensile strength compared to the as-received material in C-temper, but with an improved hardening capacity. The strain hardening behavior of friction stir processed material is discussed.