Impact tensile properties of friction welded butt joints between 6061 aluminum alloy and type 304 stainless steel

Abstract

The tensile strength and energy absorption for dissimilar metal friction welds between 6061 Al alloy and Type 304 stainless steel at high rates of loading are determined using the split Hopkinson bar. Cylindrical tensile specimens machined from as-welded butt joints of 13 mm in diameter are used in both static and impact tests. Friction welding is conducted using a brake type friction welding machine under two different welding conditions. The effects of the welding conditions and loading rate on the joint tensile properties are examined. Results show that the joint tensile properties are greatly affected by the welding parameters, and are slightly enhanced with increasing loading rate. Macroscopic observations reveal that the tensile fracture modes in the butt joint specimens vary with loading rate, depending on the welding conditions. Microhardness profiles across the weld interface are measured to investigate the extent of the heat-affected zone (HAZ). The slight enhancement of the joint tensile properties with increasing loading rate is due to the strain-rate dependence of the thermally-softened 6061 Al alloy base material.