抄録
It is highly expected that the ductility and toughness of titanium alloys bearing unstable β phase may be developed by the stress relaxation caused by strain-induced transformation. In this study, tensile test, Charpy impact test, static and dynamic fracture toughness tests were carried out at various temperatures on typical titanium alloys bearing unstable β phase. The strain-induced α″ martensitic transformation occurred in the (α+β) type Ti-6Al-2Sn-4Zr-6Mo alloy and the dynamic fracture toughness of this alloy increased considerably at 223 K. The strain-induced α' martensitic transformation occurred in the (α+β) type Ti-6Al-4V alloy, and the static and dynamic fracture toughness increased considerably at 123 and 223 K respectively and strength increased at low test temperatures in this alloy. The mechanical twin occurred in the β type Ti-15V-3Al-3Sn-3Cr alloy and the elongation of this alloy increased considerably at 123 K.
