Beta Ti alloys with low Young's modulus

Composition dependence of Young's modulus in beta Ti-V and Ti-Nb binary alloys and Sn-added ternary alloys quenched from beta phase region was investigated at room temperature in relation to the stability of beta phase. A minimum of Young's modulus in the binary alloys appears at such a composition that athermal omega phase transformation is almost completely suppressed. Formation of isothermal omega phase by aging after quenching increases Young's modulus. Sn addition to the binary alloys suppresses or retards omega transformation, thereby decreasing Young's modulus. Optimization of alloy composition in Ti-Nb-Sn alloys leads to low Young's modulus of about 40 GPa. The composition dependence of Young's modulus obtained experimentally in this study can be qualitatively explained by the theoretical discrete-variational Xalpha cluster method.