Vohra Y K, Spencer P T
Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294-1170, USA.
Phys Rev Lett. 2001 Apr 2;86(14):3068-71. doi: 10.1103/PhysRevLett.86.3068.
Group IV transition metals titanium, zirconium, and hafnium are expected to transform from an ambient hexagonal close packed (hcp, alpha-phase) to a body centered cubic (bcc, beta-phase) at high pressures. This transition path is usually facilitated by the occurrence of an intermediate hexagonal phase (distorted bcc, omega-phase). The existence of a bcc phase in zirconium and hafnium at high pressures has been known for the past ten years; however, its occurrence in titanium has been theoretically predicted but never observed. We report a novel unexpected transformation in titanium metal from an omega phase to an orthorhombic phase (distorted hcp, gamma-phase) at a pressure of 116+/-4 GPa.
第四族过渡金属钛、锆和铪预计在高压下会从常温的六方密堆积（hcp，α相）转变为体心立方（bcc，β相）。这种转变路径通常会因中间六方相（畸变bcc，ω相）的出现而变得容易。过去十年中，人们已经知道锆和铪在高压下会存在bcc相；然而，钛中bcc相的出现虽有理论预测，但从未被观测到。我们报告了钛金属在116±4吉帕的压力下发生的一种新型意外转变，即从ω相转变为正交相（畸变hcp，γ相）。
