水射流空化对NiTi形状记忆合金显微组织和超弹性的影响  

Effect of water jet cavitation on microstructure andsuperelasticity of NiTi shape memory alloy

作　　者：王雷博 陈杰 刘海霞[1] 欧阳亚东 邹杨 张永超[2] WANG Leibo;CHEN Jie;LIU Haixia;OUYANG Yadong;ZOU Yang;ZHANG Yongchao(School of Materials Science and Engineering,Jiangsu University,Zhenjiang,Jiangsu 212013,China;School of Energy and Power Engineering,Jiangsu University,Zhenjiang,Jiangsu 212013,China)

机构地区：[1]江苏大学材料科学与工程学院,江苏镇江212013 [2]江苏大学能源与动力工程学院,江苏镇江212013

出　　处：《排灌机械工程学报》2024年第3期319-324,共6页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(52175410)。

摘　　要：为了探究水射流空化对NiTi形状记忆合金的显微组织和性能的影响机制,采用水射流空化发生装置在自来水介质中对NiTi形状记忆合金进行不同时间的射流空化试验,并借助SEM,XRD,TEM、显微维氏硬度计、纳米压痕仪、激光共聚焦显微镜对样品的显微组织、物相和性能进行表征.结果表明:在射流空化20 min内,NiTi形状记忆合金表面显微硬度和超弹性均随射流时间的延长而增加;当射流时间为15 min时,NiTi形状记忆合金中出现大量位错,表面显微硬度HV达到最大值340.35(载荷约为0.245 N),与原样相比提高约34%;水射流空化对NiTi合金的影响层深度约为300μm;以纳米压痕能量恢复率来衡量合金的超弹性,在水射流空化15 min内,合金的弹性能量恢复率从38.25%提升至45.70%,表明水射流空化处理可有效提升试样的超弹性;NiTi形状记忆合金中显微硬度和超弹性的提升可归因于合金中的位错增殖.In order to investigate the influence mechanism of water jet cavitation on the microstructure and properties of NiTi shape memory alloy,the water jet cavitation experiments were carried out in tap water with different exposure times.The microstructure,phase and properties of the samples were cha-racterized by using SEM,XRD,TEM,micro-Vickers hardness tester,nano-indentation instrument and laser confocal microscope.The results show that both the surface microhardness and superelasticity of NiTi shape memory alloy increase with the prolongation of cavitation time within 20 min.When the jet cavitation time is 15 min,a large number of dislocations appear in the NiTi shape memory alloy and the surface microhardness HV reaches the maximum value of 340.35(load is 0.245 N),which is about 34%higher than that of the original sample.The depth of the influence hardened layer of water jet cavitation on NiTi alloy is about 300μm.The super elasticity of the alloy is measured by the nano-indentation energy recovery rate.The elastic energy recovery rate of the alloy increase from 38.25%to 45.70%after 15 min of water jet cavitation,indicating that water jet cavitation treatment can effectively improve the super elasticity of the sample.The increase in microhardness and super elasticity in NiTi shape memory alloy can be attributed to dislocation proliferation in the alloy.

关 键 词：射流空化 显微组织 表面形貌 显微硬度 超弹性 

分 类 号：S277.9[农业科学—农业水土工程] TH162[农业科学—农业工程]