抄録
In this report, the friction welding conditions for commercially pure titanium/pure aluminium joint were developed, and the effect of post-weld heat treatment (PWHT) on the mechanical and metallurgical properties of the complete friction welds was examined in basic research. The friction welding conditions range, which can produce the complete weld joints having more than 100% joint efficiency as joint tensile property and excellent bend ductility in the as-welded conditions, was clarified. PWHT temperatures including up to 873 K (600°C) for 36 ks (1 H) had no influence on joint mechanical properties, especially, joint tensile and bend ductility. However, they drastically decreased during PWHT at 873 K (600°C) for more than 72 ks (20 H). X-ray diffraction analysis and SEM observation confirmed that those reductions were due to the formation of large contents of Al3Ti intermetallic compound phase at the pure titanium/pure aluminium interface. The critical width of Al3Ti phase (at PWHT of 873K for 72 ks), which steeply reduced the mechanical properties, was around 10 μm. Several atomic percents of silicon concentrated in the Al3Ti phase.
