Ti 合金の高温変形挙動の Zener-Hollomon 因子による検討

概要

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High temperature deformation of pure titanium, (α+β) and β titanium alloys were studied by means of compression tests over the range of strain rate from 10^<-1> s^<-1> to 10^<-3> s^<-1> and at temperatures between 973 K and 1473 K, and the results obtained were analysed by using Zener-Hollomon parameter (Z). The following results were obtained ; (1) Maximum flow stress, σ_<max>, was correlated with working temperature, T, and strain rate, ε, approximately by the following deformation equation ; Z(=ε exp(Q/RT))=A(sin h(ασ_<max>))^n where Q : hot-working activation energy, n : stress exponent, R : gas constant, A and α : constants. (2) The value of Q in α+β phase was much larger than that in β phase. So the deformation mechanism in α+β phase must be different from that in β phase. The value of Q in β Ti was almost the same as the activation energy for the self-diffusion of Ti. (3) Deformation structure became to equiaxed microstructure by continuous recrystallization in the range of Z less than the critical value, Zc. The recrystallized grain size was determined only by the deformation condition Z, and did not depend on the initial grain size.
社団法人日本鉄鋼協会の論文
1992-08-01