材料期刊网

采用快速凝固工艺制取了不同规格的Cu-24.9wt-％Zn-4.5wt-％AJ合金带材、并通过应力-应变曲线、电阻-温度曲线、光学金相、X射线衍射、扫描电镜和透射电镜等方法研究了该合金的形状记忆性能、组织结构特征及热处理的影响。结果表明:合金喷带原始组织是单一的β细晶(晶粒尺寸约20μm);经720℃10min水淬处理后晶粒长大到100μm左右,室温下为(β+M)组织时,可以获得最佳的形状记忆性能,且避免了粗晶脆化;在应变值ε≤8％时能实现完全的记忆回复;加载变形过程中,样品表面形成的马氏体和晶粒状浮雕具有可逆性。

The shape memory properties, microstructure and the influence of heat treament on them of Cu-24.9wt-%Zn-4.5wt-%Al alloy ribbon of different sizes prepared by rapid solidification technique have been investigated by means of σ-εand R-T curves, optical metallography, X-ray diffraction, SEM and TEM. The results showed that the alloy ribbon is of a fine-grained β structure, about 20 μn, originally, and grows up to about 100μm after water quenching from 720℃ for 10 rain. For the alloy with a β+M structure at room temperature, its optimum shape memory properties may be obtained and the embrittlement by grain coarsening may be avoided. The complete memory recovery may be realized with the strain no more than 8%. The formation of granular relief and martensite on the specimen surface seems to be reversible during deformation under loading.