纳米晶NiTi形状记忆合金/Nb纳米线复合材料的超弹稳定性

中国有色金属学会  |   2022-04-14 22:46
纳米晶NiTi形状记忆合金/Nb纳米线复合材料的超弹稳定性 王涛涛1，郭方敏2，王永善1，邹祥宇1，王博1，廖仲尼1，艾桃桃1，贺志荣1 (1.陕西理工大学材料科学与工程学院，汉中723001； 2.中国石油大学（北京）新能源与材料学院，北京102249) 摘要:传统NiTi形状记忆合金因其低的强度显著降低了马氏体相变的超弹稳定性，本文通过熔炼、锻造、拔丝及退火获得了平均晶粒尺寸为14nm的NiTi和Nb纳米线复合材料，并通过循环拉伸测试研究了该复合材料马氏体相变的超弹稳定性。结果表明：用6%的应变量循环拉伸10次后，纳米晶NiTi合金/Nb纳米线复合材料呈现低的残余应变（0.52%）、高的超弹应力（748MPa）及低的超弹应力的降低率(16%)，此综合性能优于以往研究的NiTi合金。我们认为这主要源于纳米晶NiTi合金/Nb纳米线复合材料中纳米晶粒产生的细晶强化和Nb纳米线产生的第二相强度，由此显著提高复合材料的强度并抑制马氏体相变过程中塑性变形的产生，因而提高了该复合材料马氏体相变的超弹稳定性。 关键字:纳米晶；NiTi形状记忆合金；Nb纳米线；复合材料；超弹性 SuperelasticstabilityofnanocrystallineNiTishapememoryalloy/Nbnanowirecomposite WANGTao-tao1,GUOFang-min2,WANGYong-shan1,ZOUXiangyu1,WANGBo1,LIAOZhong-ni1,AITao-tao1,HEZhi-rong1 （1.SchoolofMaterialsScienceandEngineering,ShaanxiUniversityofTechnology,Hanzhong723001,China; 2.DepartmentofMaterialsScienceandEngineering,ChinaUniversityofPetroleumBeijing,Beijing102249,China） Abstract:TheconventionalcoarsedNiTishapememoryalloyoftenexhibitpoorsuperelasticstabilityduringmartensitictransformationowingtotheirlowstrength.Inthisstudy,thenanocrystallineNiTiwithanaveragegrainsizeof14nmandNbnanowirescompositeswereobtainedbymelting,forging,wiredrawingandannealing,thesuperelasticstabilityofcompositeswasinvestigatedbycyclictensiletests.WedemonstratethatthenanocrystallineNiTi/Nbnanowirecompositeexhibitslowerresidualstrain(0.52%),highersuperelasticstress(748MPa)andlowerreductionrateofsuperelasticstress(16%)aftertencyclesofloading(upto6%)-unloading,whichoverallperformanceisimprovedcomparedtopreviousNiTi-basedshapememoryalloy.WehavesuggestedthattheimprovedsuperelasticstabilityofnanocrystallineNiTi/NbnanowirecompositemainlystemsfromenhancingthestrengthoftheNiTimatrixbynano-griansandNbnanowire,whichresistingplasticdeformationduringtherepetitivemartensitictransformationandimprovingthesuperelasticstability. Keywords:nanocrystalline;NiTishapememoryalloy;Nbnanowires;composite;superelasticity