摘要
纳米畴是热弹性马氏体相变材料中的非周期性畸变区,深刻影响材料的相变行为,但其对力学行为的影响规律不清。采用真空感应熔炼、锻造、冷变形及退火制备出不同成分的含畴NiTiNb合金丝材,利用透射电镜(TEM)表征微观组织,采用变温电阻仪测试相变行为,利用万能拉伸试验机表征变温拉伸力学行为。结果表明,NiTiNb合金降温相变与力学行为均与合金成分密切相关。通过调控Ni含量与Ti+Nb含量(原子百分比)差值,可在较宽温域内获得纳米畴;当测试温度T<M^(σ)_(s)时,上述差值越大,合金屈服应力的温度依赖性(dσ/d T)越小,可在更宽的温域内展现出高强度;当测试温度T>M^(σ)_(s)时,更大的上述差值对应于合金的屈服强度与塑性同时提升。
Nanodomains are non-periodic distorted areas in thermoelastic martensitic transformation materials,profoundly affecting the phase transformation behaviors of the materials.However,their influence on the mechanical behaviors remains unclear.This study focused on different compositions of nanodomain-containing NiTiNb alloy wires prepared by vacuum induction melting,forging,cold deformation,and annealing.The microstructure was characterized using transmission electron microscopy(TEM),the transformation behaviors were investigated by probing electrical resistance at various temperatures(ER),and the mechanical behaviors were characterized using a universal tensile testing machine at different temperatures.The results show that the martensitic transformation and mechanical behaviors of NiTiNb alloys are both closely related to the difference between Ni and Ti+Nb content(atomic percentage).Tuning the content difference leads to nanodomained structure over a wide temperature range.Moreover,when T<M^(σ)_(s),the larger the content difference,the smaller the dσ/d T,and the alloy exhibits high strength over a wider temperature range.When T>M^(σ)_(s),large difference in Nb and Ti+Nb content corresponds to simultaneously improved the strength and plasticity.
作者
孙祎帆
李彦
张强
高鹏飞
于开元
SUN Yifan;LI Yan;ZHANG Qiang;GAO Pengfei;YU Kaiyuan(College of New Energy and Materials,China University of Petroleum(Beijing),Beijing 102249,China)
出处
《功能材料》
北大核心
2025年第5期5110-5114,5134,共6页
Journal of Functional Materials
基金
国家自然科学基金项目(52371207)。
关键词
NiTiNb记忆合金
纳米畴
力学性能
温度依赖性
NiTiNb shape memory alloy
nanodomain
mechanical properties
temperature dependence
作者简介
孙祎帆(1994—),女,在读博士,师承于开元教授,从事马氏体相变研究;通讯作者:于开元,E-mail:kyyu@cup.edu.cn。
