摘要
NiTiNb形状记忆合金由于其独特的相变宽滞后特性而具有极大的工程便利性,但传统成分的Ni47Ti44Nb9合金由于含有大量的稀贵金属Nb而在一定程度上限制了其大规模的商业化推广。“近单相”型NiTiNb合金则属于一类低Nb含量的NiTi基形状记忆合金,其Nb含量相较于Ni47Ti44Nb9合金降低了1/2以上。该类合金不仅同样具备较优的形状记忆性能,同时也具备较宽的相变滞后,这些特征为其应用于实际工程提供了可能。“近单相”型NiTiNb合金虽然较早就已经出现,但近年来才逐渐受到人们的关注。在该合金中,由于大部分Nb元素主要以固溶态形式存在,使其既具有NiTi二元合金的优点,同时也具备NiTiNb宽滞后合金的部分特征。目前,人们对“近单相”合金的研究较多集中于微观组织、相变行为、力学性能以及形状记忆性能等多个方面。通过研究,人们已经基本掌握了“近单相”合金的特性和主要优势,而该合金低Nb含量的特性也为深入探讨Nb元素对合金相变行为和形状回复性能的影响机理提供了便利。基于现有研究,“近单相”合金中部分Nb元素可能以β-Nb相的形式存在,其数量不仅与Nb的绝对含量有关,也与合金中的Ni和Ti的原子比有关。由于β-Nb相的塑性变形不可回复,“近单相”合金优良的形状记忆性能主要归功于其较低的β-Nb相含量。虽然有学者证实了“近单相”合金在相变滞后方面的突出表现,并由此指出固溶Nb元素对相变滞后所起的关键作用,但研究亦表明低Nb合金的相变滞后尚不能完全达到Ni47Ti44Nb9合金的水平。此外,Nb含量的降低也可能对“近单相”合金的力学性能产生不利影响。因此,具备工程应用价值的“近单相”合金的Nb含量并不宜过低。本文整理了近年来人们在“近单相”型NiTiNb合金领域的研究成果,总结了该类合金在微观组织、相变行为、力学性能以及形
NiTiNb shape memory alloy provides remarkable engineering convenience because of its unique phase transformation hysteresis.However,the use of large amount of Nb element in traditional Ni47 Ti44 Nb9 alloy restricts the broader commercial application of the alloy."Near single-phase" NiTiNb alloy is a sort of NiTi based shape memory alloy with low Nb content.The content of Nb in "near single-phase" alloy decreases more than a half compared with Ni47 Ti44 Nb9 alloy.The alloy possesses not only good shape memory property but also relative wide phase transformation hysteresis,which makes it promising in terms of industrial engineering application. Though "near single-phase" NiTiNb alloy appeared for many years,not until rencent years has it attracted much attention among researchers.Since most Nb atoms are dissolved in the NiTi matrix,the alloy has combined virtues of both NiTi binary alloy and NiTiNb wide hysteresis alloy.To date,most investigations about "near single-phase" alloy are focused on its microstructure,phase transformation behaviors,mechanical properties and shape memory effect.Character and main advantages of the alloy have been obtained through these studies.Moreover,low Nb content of the alloy also gives convenience for people to discuss the effect of Nb element on transformation behavior and shape memory property. Based on existing studies,part of the Nb atoms may appear as β-Nb phase in "near single-phase" alloy.The amount of β-Nb phase depends on not only the amount of Nb element in the alloy,but also the Ni/Ti ratio.Since the plastic deformation of β-Nb phase is not recoverable,the good shape memory properties of "near single phase" alloys should thus be attributed to the rather low content of β-Nb.Some researchers have proved the excellent shape memory property of "near single-phase" alloy,and they also indicate that Nb atoms which dissolved in NiTi matrix are the predominant factor accounting for the wide hysteresis.Other research,however,also shows that the hysteresis of "near single-phase"
作者
张永皞
孟玉堂
范啟超
孙明艳
黄姝珂
ZHANG Yonghao;MENG Yutang;FAN Qichao;SUN Mingyan;HUANG Shuke(Institute of Machinery Manufacturing Technology,China Academy of Engineering Physics,Mianyang 621999)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2019年第19期3272-3276,共5页
Materials Reports
基金
中国工程物理研究院科学技术发展基金(2015B0302060)
四川省应用基础研究计划(2017JY0319)~~
