1989 年 53 巻 9 号 p. 892-897
The numerical simulation was examined in superplastic deformation of an Al-33%Cu eutectic alloy in order to show the neck shape change. The simulation was based on the experimental constitutive equations in consideration of the strain rate sensitivity m and the flow hardening parameter γ distributions as well as the strain rate distribution in the specimen. The simulated results were compared with experimental results of the same shape specimen.
In regions I and II, where the deformation induced grain growth was independent of strain rate, the simulated results showed that I≡(γ−1)⁄m>−2 in any part of the specimen and the neck became broadened and diffuse. In these regions the simulated results were well coincide with the experimental results.
On the other hand, in region III it was simulated that the instability and strain rate would become larger rapidly at the narrowest part of the specimen, and that the specimen would become constricted sharply.