Effect of welding speed on tensile strength of friction stir welds of Al-Cu-Mg-Si alloy

Abstract

The effect of welding speed on the tensile properties of the friction stir welds of Al-1.7mass%Cu-1.0mass%Mg-0.8mass%Si alloy has been investigated. The increase of welding speed improved the tensile properties of the friction stir weld after the postweld heat treatment at 468 K for 8 h. The increase in tensile strength of the friction stir welds was attributed to the reduced time above the overaging temperature in the HAZ where the tensile fractures occurred. The increase of welding speed decreased the density of the coarse precipitates with a length of 500 nm in the HAZ.