Micro-characteristic of Strengthened Al0.1CoCrFeNi Alloy from Aluminum-Addition Friction Stir Processing

1060 Al and Al0.1CoCrFeNi are friction stir lap welded in this study in order to improve the microstructure and mechanical property of the high-entropy alloy by adding Al element into the alloy through friction stir processing. The results indicate that a crescent-shaped aluminum-addition zone featured by limited upward material flow is formed in the high-entropy alloy. The aluminum-addition friction stir processing leads to the formation of fine and homogeneously distributed microstructures and the occurrence of body-centered cubic phases in the high-entropy alloy. Owing to the synthetical strengthening effects caused by friction stir modification and Al content increase, the hardness of the Al0.1CoCrFeNi alloy is increased significantly from 100 Hv to an average value over 400 Hv and a maximum value of 600 Hv. The present study is able to provide an effective approach for the preparation and strengthening of high-entropy alloys.