Joining of Zr51Ti5Ni10Cu25Al9 BMG to aluminum alloy by friction stir welding

Plates of Zr51Ti5Ni10Cu25Al9 bulk metallic glass (BMG) and 7075 aluminum alloy were successfully joined by friction stir welding (FSW). On the aluminum alloy side near the interface, some BMG fragments with irregular shapes and different sizes are found distributed in the nugget zone. The hardness of 7075 aluminum alloy first decreases and then increases as the distance away from the weld interface. The harness of BMG firstly increases as the position moves away from the weld interface. Then the hardness decreases and keeps constant at about 540 Hy. The evolution of the hardness in the BMG side is closely related to the variation of free volume in the glassy alloy. (C) 2015 Elsevier Ltd. All rights reserved.