H. Saito, T. Inamura, H. Hosoda, K. Wakashima, Tokyo Institute of Technology, Yokohama, Japan; S. Miyazaki, University of Tsukuba, Tsukuba, Japan
Although shape memory effect of Ti-Nb ternary alloys was widely investigated, comparably limited data were obtained for the Ti-Mo base alloys: Ti-Mo-Al (Kimura et al. 1985, Sasano el al. 1990 and Hosoda et al. 2001), Ti-Mo-Ga (Hosoda et al. 2001 and Kim el al. 2004), Ti-Mo-Sn, Ti-Mo-Sc and Ti-Mo-Ag (Maeshima et al. 2004) and Ti-Mo-N (Tomio et al. 2005). It was found that martensitic transformation temperature form β parent phase to α” martensite phase of Ti alloys is much lowered by Mo addition than Nb addition. In order to understand the effect of ternary addition on shape memory effect and mechanical property comprehensively, Ti-Mo base alloys containing several ternary elements were investigated and compared to Ti-Nb base alloys. Besides, effect of ageing treatment was also studied. It was found that, for example, Ti-Mo base alloys become brittle by ageing at 773K due to ω-embrittlement whilst no serious embrittlement occurs in the Ti-Nb base alloys.
Summary: Although shape memory effect of Ti-Nb ternary alloys was widely investigated, comparably limited data were obtained for the Ti-Mo base alloys: Ti-Mo-Al (Kimura et al. 1985, Sasano el al. 1990 and Hosoda et al. 2001), Ti-Mo-Ga (Hosoda et al. 2001 and Kim el al. 2004), Ti-Mo-Sn, Ti-Mo-Sc and Ti-Mo-Ag (Maeshima et al. 2004) and Ti-Mo-N (Tomio et al. 2005). It was found that martensitic transformation temperature form ƒÒ parent phase to
a¡¨ martensite phase of Ti alloys is much lowered by Mo addition than Nb addition. In order to understand the effect of ternary addition on shape memory effect and mechanical property comprehensively, Ti-Mo base alloys containing several ternary elements were investigated and compared to Ti-Nb base alloys. Besides, effect of ageing treatment was also studied. It was found that, for example, Ti-Mo base alloys become brittle by ageing at 773K due to
w-embrittlement whilst no serious embrittlement occurs in the Ti-Nb base alloys.
