多晶Cu-Al-Ni合金的软性第二相构建及高温双程形状记忆效应

随着科技的发展，Ti-Ni合金已经不能满足高温驱动领域对记忆合金的使用需求，开发具有优异双程形状记忆效应的低成本高温形状记忆合金很有必要。Cu-Al-Ni合金成本低，其单晶具有良好的双程形状记忆效应，是一种应用潜力巨大的高温形状记忆合金。然而，严重的多晶脆性制约了Cu-Al-Ni合金的双程形状记忆效应，进而降低了其实际应用的可能性。本项目针对多晶Cu-Al-Ni合金的力学性能和双程形状记忆效应这两个短板，选择工艺最简单的合金化法，通过添加Nb元素，引入软性第二相，改善合金脆性。研究软性第二相对多晶Cu-Al-Ni合金双程形状记忆效应的影响规律，利用软性第二相产生的内应力场配合适当的热机械训练，提高双程可逆应变量；确立多晶Cu-Al-Ni合金最佳制备和热处理工艺设计准则，并优化热机械训练工艺，开发具有优良力学性能和双程形状记忆效应的低成本高温形状记忆合金材料。

With the development of science and technology, Ti-Ni alloy has been unable to meet the demand for memory alloy in the high-temperature driving field, so it is necessary to develop a low-cost high-temperature shape memory alloy with excellent two-way shape memory effect (TWSME). Cu-Al-Ni alloys are low cost, and its single crystal has good two-way shape memory effect as a high-temperature shape memory alloy (HTSMA) with great application potential. However, the serious brittleness of polycrystalline Cu-Al-Ni alloy restricts its TWSME and reduces the possibility of practical application. In this project, aiming at the poor mechanical properties and TWSME of polycrystalline Cu-Al-Ni alloy, the simplest method is selected, the Nb elements will be added to improve the brittleness by the soft second phase formation. The influence of soft second phase on TWSME of polycrystalline Cu-Al-Ni HTSMA is revealed. The internal stress field generated by soft second phase is used to enhance the two-way reversible strain through proper thermal mechanical training. The best preparation and heat treatment process of polycrystalline Cu-Al-Ni alloy are established, and the training method is also optimized. The low-cost HTSMA material with outstanding mechanical properties and TWSME is developed.