预拉伸形变对Mg-Zn-Sr-Zr-Mn合金降解行为的影响  

Effect of Pre-stretching Deformation on Degradation of Mg-Zn-Sr-Zr-Mn Alloy

作　　者：张源 郑瑞宁 刘芸 赵冠璋 田亚强 郑小平 陈连生 Zhang Yuan;Zheng Ruining;Liu Yun;Zhao Guanzhang;Tian Yaqiang;Zheng Xiaoping;Chen Liansheng(Key Laboratory of the Ministry of Education for Modern Metallurgy Technology,North China University of Science and Technology,Tangshan 063210,China)

机构地区：[1]华北理工大学、现代冶金技术教育部重点实验室,河北唐山063210

出　　处：《稀有金属材料与工程》2023年第3期1045-1054,共10页Rare Metal Materials and Engineering

基　　金：河北省自然科学基金(E2020209153);河北省省属高校基本科研业务费(JYG2019001);唐山市科学技术研究与发展计划(20130205b);新金属材料国家重点实验室开放基金(2020-Z12)。

摘　　要：镁合金具有优异的生物相容性和独特降解性,但其在生理环境中的耐蚀性能较差,严重制约了其在临床应用中的发展。使用预拉伸工艺制备Mg-Zn-Sr-Zr-Mn新型镁合金,通过XRD、OM和SEM探究预拉伸形变量与显微组织、腐蚀速率和膜层形貌间的关系。结果表明:随预拉伸形变量的增大(2%、4%、6%),合金晶粒尺寸被逐渐拉长,孪晶数目逐渐增多,析出相离散程度逐渐增大。4%预拉伸合金由于适量孪晶的出现及析出相离散程度的增大,增加了电偶腐蚀形核点位,加速了合金表面均匀氧化产物的快速产生,增大了合金极化电阻阻值;3种预拉伸合金电化学(0.38、0.25、0.74 mm·a^(-1))及失重速率(2.85、1.83、5.88 mm·a^(-1))均呈现先降低后升高的趋势。4%预拉伸合金具有较高的耐蚀性证明适当的预拉伸变形能提高界面析出相的连续性,阻碍腐蚀进程,对合金耐腐蚀性能起到积极作用。而当预拉伸形变量继续增加,产生大量位错,创造氢扩散路径,有利于氢富集,导致合金耐蚀性下降。此外,适当的预拉伸形变通过改变残余应力的重新分布,提高腐蚀均匀性,同时提高膜层致密性与连续性,延缓腐蚀进程。Magnesium alloys own excellent biocompatibilities and unique degradation characteristics.However,the poor corrosion resistance in physiological environment seriously restricts its development in clinical applications.Mg-Zn-Sr-Zr-Mn alloys were prepared by pre-tensile process.The relationship between the microstructure,corrosion rate and film layer morphology and the pre-tensile type variables was investigated by XRD,OM and SEM.The results show that with the increase deformation of pre-stretching,the grain sizes are gradually elongated,the numbers of twins are increased,and the dispersion degrees of precipitated phases gradually increase.The corrosion rate of the three pre-stretching alloys in electrochemical(0.38,0.25,0.74 mm·a^(-1))and mass loss(2.85,1.83,5.88 mm·a^(-1))both decreases firstly and then increases.Therein,the 4%pre-stretching alloy has high corrosion resistance,which indicates that appropriate pre-tensile deformation can improve the continuity of the precipitated phase at the interface,hinder the corrosion process,and play a positive role in the corrosion properties of the alloys.However,when the pre-tensile deformation continues to increase,a large number of dislocations will be generated and hydrogen diffusion path will be created,which is conducive to hydrogen enrichment and leads to the decrease of corrosion resistance.Moreover,appropriate pre-tensile deformation can improve the corrosion uniformity,densification and continuity of the film-layer,and delay the corrosion process by changing the redistribution of residual-stress.

关 键 词：医用镁合金 预拉伸形变 膜层降解 膜层致密性 腐蚀速率 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG178.2[金属学及工艺—金属材料]