Effect of multi-pass friction stir processing on the microstructure and hardness of AA1100/Al13Fe4 in situ composites

Abstract

In situ Al-Al13Fe4 surface composites were synthesized via friction stir processing (FSP) at aluminium plate with the addition of Fe2O3 particles and the effect of multi-pass of the FSP on microstructure and hardness was investigated. The defect free surface composites which consisted of a fine grained aluminium matrix (2-10 mu m), Al13Fe4 particles (>250 nm and <100 nm) as well as some unreacted elemental iron and iron oxide fragments, were successfully produced. Compared with the base metal and the FSPed samples without particles addition, an improvement in hardness (up to 300%) was achieved in the surface composites. Also, a significant grain refining was detected.