マグネシウム特集号 Ｍｇ‐３ｍｏｌ％Ａｌ固溶体合金押出材のクリープ挙動に及ぼす応力負荷方向の影響

Abstract

Creep behavior of an extruded Mg-3 mol%Al solid solution alloy has been examined at 600 and 650K where the activation energy of creep is similar to that for diffusion. Compression creep tests were performed on longitudinal samples and transverse samples. Two types of creep behavior, termed "Alloy" and "Metal", were observed on both samples at lower and higher stresses, respectively. Stress exponent at the lower stress range is about 3, and 6 at the higher stress range. A change in the type of creep curves is observed at 650K. The creep characteristics and the transition stress from "Alloy" to "Metal" type depend on the stress direction so that the transition occurs at lower stress in transverse samples. These results are discussed in terms of the breakaway stresses from solute atmosphere on different slip planes.