富Mn NiMnGa合金γ相的微观结构与热力学性能研究  

Microstructure,Thermal and Mechanical Properties ofγPhase in Mn-rich NiMnGa Alloy

作　　者：周岳匆 欧阳晟 邓翠贞 龙建 Zhou Yuecong;Ouyang Sheng;Deng Cuizhen;Long Jian(School of Materials Science and Engineering,Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]南昌航空大学材料科学与工程学院,江西南昌330063

出　　处：《稀有金属材料与工程》2025年第3期765-773,共9页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(52001156)。

摘　　要：传统Ni-Mn-Ga合金脆性大,虽然富Ni的Ni-Mn-Ga合金显著提升了合金的韧性,形状记忆效应却大幅度下降,而富Mn的Ni-Mn-Ga合金具有较高的马氏体相变温度、良好的热稳定性和适中的形状记忆性能。研究了Ni_(54)Mn_(28+x)Ga_(18-x)(x=0,4,7,9,13)γ相的微观结构及合金的热力学性能。随着Mn含量的增加,γ相开始出现,晶粒内存在“微米片层包含纳米片层”微观结构。微米片层由两变体组成,变体包含一对呈{011}孪晶关系的纳米片层,该片层是面心四方结构。随着Mn含量的增加,压缩应力从914 MPa增加到2175 MPa,压缩应变从14%增加到26%,但其形状记忆效应逐渐降低,马氏体相变温度从352℃提高至585℃。富Mn Ni-Mn-Ga合金层片γ相的引入对合金韧性增强虽不如富Ni合金,但合金马氏体相变温度更高。Brittleness of traditional Ni-Mn-Ga alloy is a marjor obstacle for its practical applications,as actuators and sensors.The Ni-rich Ni-Mn-Ga alloy can significantly improve the ductility.However,the shape memory strain is significantly reduced.Higher martensitic transformation temperature,good thermal stability and moderate shape memory property are shown in Mn-rich Ni-Mn-Ga.In the present work,microstructural feature,mechanical properties and thermal property of Ni_(54)Mn_(28+x)Ga_(18-x)(x=0,4,7,9,13)were investigated.As the Mn content increases,theγphase appears,with is a face centered tetragonal(fct)structure,and aγgrain contains a hierarchical“nano-lamellae forming within microlamellae”microstructure.A micro-lamella consists of two variants,each variant has a pair of nano-lamellae,and they are{011}twin related.Owing to the introduction of lamellarγ,the ductility is improved.With the increase in Mn content,the compressive stress increases from 914 MPa to 2175 MPa,and the compressive strain increases from 14%to 26%.The martensitic transformation temperature of such series of alloys increases from 352℃to 585℃.For Mn-rich Ni-Mn-Ga alloy,the ductility improvement is inferior to that of Ni-rich alloy,but the martensitic transformation temperature is higher.

关 键 词：NI-MN-GA Γ相 亚结构 纳米孪晶 韧性增强 马氏体相变温度 

分 类 号：TG146[一般工业技术—材料科学与工程] TB381[金属学及工艺—金属材料]