Effect of backing plate on microstructure and properties of friction stir welded 2195-O alloy

Abstract

The effect of two different backing plate (BP) conditions on the microstructure and resulting mechanical properties of friction stir welded Al-Cu-Li alloy (2195-O) was investigated. This study shows that Copper-BP with lower welding temperature and higher cooling rate, forms finer grains in the nugget, resulting in higher yield strength. The steel-BP weld with higher peak temperature and lower cooling rate results in larger grain size in the nugget and greater solid solution strengthening. While the weld with the steel-BP had a marginally smaller yield strength, it displayed much greater work hardening rate along with better ageing response. © 2023