Abstract
The tensile strength and energy absorption of 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. Round tensile specimens machined from as-welded butt joints of 12 mm diameter are used in both static and impact tension tests. Friction welding is conducted using a brake type friction welding machine under two different welding conditions. The effects of welding parameters and loading rate on the tensile properties of friction welded butt joints are investigated. It is demonstrated that the tensile properties are greatly affected by the welding conditions, and are slightly enhanced with increasing loading rate. Macroscopic observations reveal that the tensile fracture mode of friction welded butt joints varies with loading rate, depending on the welding conditions. Microhardness measurements are performed to examine the extent of the heat-affected zone (HAZ) across the weld interface. The slight enhancement in the tensile properties of friction welded butt joints with increasing loading rate is due to the strain rate dependence of the thermally-softened 6061 Al alloy base material.
