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郝雨筱,童伟,徐钧,彭良明*.Ni含量对Ni-Mn-Ga高温形状记忆合金相转变及力学性能影响[J].实验力学,2019,34(5):748~758

Ni含量对Ni-Mn-Ga高温形状记忆合金相转变及力学性能影响

Effects of Ni content on phase transformation behavior and mechanical properties of Ni_54+xMn₂₅Ga_21-x high temperature shape memory alloy

投稿时间：2019-03-22 修订日期：2019-04-26

DOI：10.7520/1001-4888-19-040

中文关键词: Ni-Mn-Ga合金形状记忆效应微观组织马氏体相变强度与塑性

英文关键词:Ni-Mn-Ga alloy shape memory effect microstructure martensitic transformation strength and ductility

基金项目:

作者	单位
郝雨筱	中国科学技术大学，近代力学系，中科院材料力学行为和设计重点实验室，安徽合肥 230027
童伟	中国科学技术大学，近代力学系，中科院材料力学行为和设计重点实验室，安徽合肥 230027
徐钧	中国科学技术大学，近代力学系，中科院材料力学行为和设计重点实验室，安徽合肥 230027
彭良明*	中国科学技术大学，近代力学系，中科院材料力学行为和设计重点实验室，安徽合肥 230027

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中文摘要:

研究了Ni_54+xMn₂₅Ga_21-x (x=0~4) 高温形状记忆合金体系中,Ni元素含量对微观结构、马氏体相变特性及准静态压缩强度、塑性与不同预应变条件下记忆特性的影响。研究发现，当Ni含量较低时，合金由单相正方马氏体相组成，高Ni含量合金则呈现由马氏体和面心立方γ相组成的双相组织，每个马氏体集群由四个不同取向的变体组成，变体间存在I型或II型孪生关系。由于马氏体电子浓度和尺寸因素的影响，马氏体相变特征温度随Ni含量增加显著提高。通过添加Ni替代Ga引入γ相可以显著改善合金的压缩强度和塑性，其中Ni₅₆Mn₂₅Ga₁₉合金呈现较优异的力学性能。但合金中γ相含量较多时，形状记忆效应和形状回复率逐渐减弱。因此，进一步优化合金综合性能时需兼顾强度、塑性和形状记忆性能之间的平衡。

英文摘要:

Influences of Ni content on the martensitic transformation behavior, microstructure and mechanical properties of polycrystalline Ni_54+xMn₂₅Ga_21-x (x=0~4) high-temperature shape memory alloy was investigated. A single martensite phase with tetragonal crystal structure for x<3 was obtained whereas the alloy with x≥3 exhibited dual phases of martensite and face-centered cubic γ phase. Each martensite colony is composed of four variants with different orientations, which are related to one another by either type-I or type-II twin relation. Martensitic transformation temperatures were improved dramatically with increasing Ni content, which can be attributed to the combinative effects of increasing electron concentration and tetragonality of martensite. Higher Ni addition led to the formation of γ phase, resulting in significant improvement in both compressive strength and ductility. In contrast, the shape memory effect and recovery ratio for the alloy containing higher γ phase were reduced sharply. Therefore, the trade-off among strength, ductility and shape memory effect should be taken into account in further investigations.

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