実用5083合金の超塑性特性の実験的評価とその変形機構の解析

概要

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In order to determine the controlling mechanism during the superplastic deformation process of a commercial 5083 Al-Mg alloy, superplastic properties have been investigated using constant strainrate tensile tests at the temperatures between 773 and 843 K and over a strain rate range from 10^<-5> to 10^<-1>s^<-1>. The analysis from the experimental results reveals that the true stress exponent is two, and the true activation energy for superplastic flow is similar to lattice self-diffusion of aluminum (142 kJ/mol). All mechanical data can be represented by a single constitutive equation for superplasticity, which indicates that the dominant superplastic deformation mechanism is grain boundary sliding and the rate-controlling step in accommodation process is considered to be controlled by diffusional-flow-related phenomena within the grains during the superplastic flow. Also the microstructual dynamics with grain growth and cavitation during superplastic straining can reveal that the grain growth causes increase in flow stress and decreases in strain-rate sensitivity of flow stress, and the extensive cavitation leads a limited value in elongation-to-failure.
一般社団法人日本機械学会の論文
1998-05-25