Bulk glass formation in the Ni-Zr-Ti-Nb-Si-Sn alloy system

摘要

In this study, the effect of addition of Nb on glass formation in Ni-Ti-Zr-Si-Sn alloys has been studied. The composition range for bulk glass formation with D_(max) > 2 mm (D_(max), maximum diameter for glass formation by injection cast method) becomes wider when compared with the non-Nb-containing alloy. The DELTA T_x (= T_x - T_g; T_x, crystallization onset temperature; T_g, glass transition temperature), T_(rg) (= T_g/T_1; T_1, liquidus temperature) and gamma [ = T_x/(T_1 + T_g)] values for the alloys D_(max) > 2 mm are in the range of 40-59, 0.638-0.651, and 0.410-0.419, respectively. The compositions of the alloys (D_(max) > 2 mm) are closer to pseudo-eutectic composition than that of the alloy without Nb, showing an improved glass forming ability. The critical cooling rate for glass formation (D_(max) = 5 mm) is estimated to be order of approximately 40 K/s.