MICROSTRUCTURAL AND MECHANICAL INVESTIGATIONS OF FRICTION STIR WELDED TI/TI- AND TI-ALLOY/TI-ALLOY-JOINTS

摘要

Friction Stir Welding (FSW) is an efficient welding technique to join light-weight materials in ductile material condition. Especially for aerospace applications FSW of cp-titanium and Ti-alloys is of high scientific and technological interest. At the Institute of Materials Science and Engineering (WKK) friction stir welds of 1.2 mm thick cp-titanium and Ti6A14V sheets were produced. To analyze the microstructure of the welding zone in detail light- and scanning electron-microscopic investigations were carried out. By EBSD it was possible to describe the material flow in the welding zone. The mechanical properties were characterized by two dimensional micro-hardness measurements and strain controlled tensile tests. For welds with cp-titanium a yield point of 345 MPa and an ultimate tensile strength of 450 MPa were achieved.