摘要
利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、能谱仪(EDS)、腐蚀失重实验以及电化学工作站研究了退火处理对高压扭转变形(HPT)ZXJ310合金的微观组织和体外降解性能的影响。结果表明:高压扭转态ZXJ310镁合金在150℃退火时,随着退火时间延长(0~4 h),合金的平均晶粒尺寸由高压扭转态的98.3 nm,分别增长至169.8,217.6,220.2和259.5 nm。通过TEM观察可知,ZXJ310镁合金中的位错密度明显降低;电化学测试显示:随着退火时间延长,腐蚀电位明显增加,ZXJ310镁合金Nyquist图谱中的容抗弧半径逐渐增加,退火4 h后高压扭转ZXJ310镁合金的电化学腐蚀速率可以降低至0.32 mm·y^(-1);ZXJ310镁合金在模拟体液中的浸泡失重试验结果也表现出同样的趋势,3~4 h退火后的ZXJ310镁合金的耐蚀性显著提升;对ZXJ310镁合金的腐蚀产物分析可知,退火处理显著改善合金在模拟体液(SBF)溶液中的浸泡腐蚀行为,增加腐蚀产物膜层的致密性和稳定性,但不会对合金腐蚀产物的类型产生影响。不同状态下ZXJ310镁合金在相同浸泡条件下产生的腐蚀产物种类没有区别,浸泡120 h后均能产生含羟基磷灰石的Ca-P化合物。
In recent years,the degradable metals represented by magnesium and magnesium alloys have gradually become a research hotspot for fracture internal fixation and bone defect repair materials due to their good biocompatibility,suitable elastic modulus and degradable characteristics,and are a type of medical metal materials with great application potential.ZXJ310 magnesium alloy has the characteristics of full nutrient composition,but it is found that the alloy still has the problems of non-uniform corrosion,high corrosion rate and serious gas production.The use of severe plastic deformation(SPD) process can refine the grains,thereby increasing the strength of the alloy and improving the corrosion resistance,and the application of the large plastic deformation process to magnesium and magnesium alloy processing has improved its potential for biomedical applications.Commonly used methods include equal channel angular pressing(ECAP) and high pressure torsion(HPT).HPT is more suitable for the metal materials with close-packed hexagonal structure that are difficult to deform,and HPT can significantly reduce the grain size of magnesium alloys,and some scientists have shown that the distribution and number of the second phase will be improved during the high-pressure torsional process,which can help improve the corrosion resistance of the alloy.In the early stage,a bulk ZXJ310 alloy with nanocrystalline characteristics was successfully prepared by exploring HPT parameters,with a good second phase dispersion distribution state.HPT was carried out at room temperature using the HPT-4 high-pressure torsion equipment manufactured by TRANSMST,Austria in this study,and the specimen size was Ф10 mm×1.0 mm.According to the preliminary process study,the torsion cycle was set to 15 cycles,the test pressure was 7.85 GPa,and the rotational speed was set to 1 r·min~(-1).There were high residual stresses and crystal defects in the processing process of HPT alloy,such as high-density dislocations,and it was necessary to combine the low-temperature annealing process to improve the residual stress and crystal defects and other factors that were not conducive to corrosion of HPT alloy.The effects of annealing treatment on the microstructure and in vitro degradation performance of ZXJ310 magnesium alloy after high pressure torsion were studied using scanning electron microscopy(SEM),transmission electron microscopy(TEM),energy dispersive spectroscopy(EDS),weight loss measurement and electrochemical test.The results showed that when HPT state ZXJ310 magnesium alloy annealed at 150 ℃,with the extension of the annealing time,the microstructure was observed and the grain size of the alloy gradually increased,and the average grain size increased from 98.3 nm in HPT state to 169.8,217.6,220.2 and 259.5 nm after 1,2,3 and 4 h annealing,respectively.At the same time,TEM images showed that the dislocation density in HPT stateZXJ310 magnesium alloy was significantly reduced.The electrochemical test showed that the corrosion potential of the high-pressure torsion alloy increased significantly with the annealing time from 1 to 4 h,and the capacitive arc radius in Nyquist spectrum of the alloy gradually increased,and the electrochemical corrosion rate of the alloy could be reduced to 0.32 mm·y~(-1) after annealing for 4 h.The results of immersion weight loss of alloy in simulated body fluids also showed the same trend,and the corrosion resistance of high-pressure torsion alloy after 3~4 h annealing was significantly improved.The annealing treatment significantly improved the immersion corrosion behavior of the alloy in simulated body fluids(SBF) and increased the compactness and stability of the corrosion product film,but did not affect the type of alloy corrosion products.There was no difference in the types of corrosion products produced by alloys under the same immersion conditions under different states.When the immersion time was extended to 120 h,the proportion of Ca and P atoms in the corrosion products on the surface of the alloy continued to increase,and the ratio of Ca/P(atomic ratio) increased to 1.68,indicating that Ca-P compounds containing hydroxyapatite(HA) had been formed in the alloy,which was the main component of inorganic components of human bone.After 24 h of immersion of HPT state ZXJ310 magnesium alloy after annealing at 150 ℃ for 4 h,the corrosion product film formed on the surface of the alloy was relatively smooth.When the corrosion time was extended to 72 h,the compactness of the corrosion film layer was further improved,and the dense protective layer formed by the deposition of the corrosion products could effectively protect the alloy matrix.When the corrosion time was extended to 120 h,a large number of corrosion products accumulated on the surface of the alloy.By observing the morphology of the corrosion products after removing them,the roughness of the alloy was significantly reduced compared with HPT state alloy,which further indicated that the corrosion resistance of the alloy could be significantly improved by eliminating the microscopic defects generated during the deformation process by annealing.In summary,annealing at 150 ℃ for 3~4 h could obtain uniform fine structure and lower corrosion weight loss rate.
作者
张家振
马鸣龙
李永军
孙昭乾
史文鹏
郝雪龙
张奎
Zhang Jiazhen;Ma Minglong;Li Yongjun;Sun Zhaoqian;Shi Wenpeng;Hao Xuelong;Zhang Kui(State Key Laboratory of Nonferrous Metals and Processes,China GRINM Co.,Ltd.,Beijing 100088,China;GRIMAT Engineering Institute Co.,Ltd.,Beijing 101407,China;General Research Institute for Nonferrous Met-als,Beijing 100088,China;National Analysis and Testing Center for Non-Ferrous Metals and Electronic Materi-als,National Standard(Beijing)Inspection and Certification Co.,Ltd.,Beijing,101407,China)
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2024年第5期609-617,共9页
Chinese Journal of Rare Metals
基金
国家重点研发计划项目(2021YFB3701002)资助。
作者简介
张家振(1982-),男,山东聊城人,博士研究生,高级工程师,研究方向:生物医用镁合金及应用,E-mail:zhangjz@cmde.org.cn;通信作者:李永军,教授,电话:010-60662665,E-mail:lyj@grinm.com;通信作者:郝雪龙,教授,电话:010-61681168,E-mail:xlhaogrinm@126.com。
