In-process cooling of friction stir extruded joints for increased weld performance via compressed air, water, granulated dry ice, and liquid nitrogen

Joining of aluminum alloy AA6061 to mild steel was achieved using a friction stir extrusion (FSE) method in which processed extruded into preformed dovetail groove. These joints were subject various in-process cooling (IPC) methods via compressed air, water, granulated dry ice, and liquid nitrogen as well varying weld pitches (WP) the following rotational translational (inches per minute, IPM) parameters: 1500RPM-3IPM, 1500RPM-2IPM, 1000RPM-3IPM, 1000RPM-2IPM. Rockwell hardness testing lap shear tensile then used evaluate effectiveness IPC by comparison uncooled joints. tests revealed an increase 4.1% 3.1% performance water cooled ice respectively compared weld. Additionally, average joint strength increased at maximum 4.5% for joints, 3.7% air welds, 3.5% 1.8% welds. The use sources also that higher WP, stronger joint. Thus, WP (revolution inch, RPI) order descending are follows: 750 RPI, 500 333 RPI. novelty this research comes from investigation on FSE past has butt introduction improved with yielding greatest measured improvement.