高功能疲劳特性TiNiCu基形状记忆块体合金研究

In order to solve the degradation of shape memory alloys during long term service and meet the urgent requirements of elastocaloric cooling et al. for bulk materials, a method combined melt-spinning and spark plasms sintering is proposed to prepare TiNiCu-based bulk shape memory alloys with high functional properties. Firstly, the influence of processing parameters on microstructure of TiNiCu-based bulk alloys will be studied systematically. The emphasis will be placed on the formation mechanism of precipitates during sintering. After that, the cycling stability of martensitic transformation and superelasticity of TiNiCu-based bulk alloys will be investigated. The microstructual mechanism of the influence of processing parameters on the funcitonal fagitue properties will be clarified. Finally, The relationship among the processing parameters, microstructure evolution and functional fatigue properties will be estabilished. The present work may provide the theoretical foundation for engineering application of TiNiCu-based bulk shape memory alloys with high functional fatigue, but aslo enrich the theory of martensitic transformation.

针对形状记忆合金长期服役下性能衰减问题以及弹热制冷等对块体合金的迫切需求，提出利用甩带法与放电等离子烧结相结合的方法制备功能疲劳特性优异的TiNiCu基形状记忆块体合金，系统研究制备工艺对TiNiCu基块体合金微观组织的影响，重点关注放电等离子烧结过程中析出相形成机理；研究TiNiCu基块体合金的马氏体相变行为与超弹性性能的稳定性，阐明制备工艺影响块体合金功能疲劳性能的微观机制；建立制备工艺参数-微观组织演化-功能疲劳特性之间的内在联系，为具有优异功能疲劳特性的TiNiCu基块体合金的工程应用奠定理论基础。相关研究成果还将丰富马氏体相变理论。

TiNiCu基形状记忆合金由于具有抗疲劳性能好、阻尼性能强、耐腐蚀性好、窄滞后和响应速度快等特点，使得在MEMS领域具有很大应用空间。但在使用过程中随着载荷循环次数的增加，合金形状记忆效应会发生衰退。为提高TiNiCu基形状记忆合金的循环稳定性能，采用单辊急冷甩带法制备TiNiCu基合金薄带，并通过不同退火工艺处理改善合金显微组织，研究合金显微组织对马氏体相变行为及循环稳定性的影响，退火工艺对Ti2Cu析出相形成机理，研究TiNiCu基合金的马氏体相变行为与热循环稳定性。阐明制备工艺影响合金功能疲劳性能的微观机制；建立制备工艺参数-微观组织演化-功能疲劳特性之间的内在联系，为具有优异功能疲劳特性的TiNiCu基合金的工程应用奠定理论基础。