摘要
通过等通道角挤压(ECAP)的方法制备了超细晶纯Ti,利用EBSD技术研究了2~4道次样品晶粒尺寸、基面织构强度和大小角度晶界的变化规律。同时,采用动电位极化和EIS的方法研究不同晶粒尺寸样品的耐模拟海水腐蚀性能。结果表明:经过2道次ECAP,原始粗晶纯Ti的晶粒尺寸和基面织构强度减小,小角度晶界分数急剧增加。随着挤压道次的增加,纯Ti的晶粒尺寸继续减小,基面织构强度先增大后减少,小角度晶界分数逐渐降低。相比于原始粗晶纯Ti,所有ECAP制备的超细晶纯Ti的腐蚀电流密度和腐蚀速率明显降低,极化电阻增大,表现出更加优异的耐海水腐蚀性能。另一方面,随着ECAP道次的增加,纯Ti的耐海水腐蚀性能并不是呈单调增加的关系,3道次试样的耐腐蚀性能最优,这主要归因于晶粒尺寸、基面织构和晶界特征分布的耦合影响,其中基面织构强度的影响占据主导地位。
Titanium alloy has extensive applications in the field of chemical, biomedical and marine engineering due to high specific strength and excellent corrosion resistance. Ultrafine-grained(UFG) and nanocrystalline(NC) materials with unique properties processed by severe plastic deformation are widely studied in recent decades. In comparison with large number researches on mechanical behavior of UFG/NC materials, corrosion resistance is rarely studied and results indicated inconsistent, even within the same alloy system. In this work, ultrafine-grained pure Ti was fabricated by equal channel angular pressing(ECAP) with 2~4 passes. Grain size, crystallographic texture and grain boundary character distribution of samples were characterized by EBSD. At the same time, dynamic potential polarization and EIS methods were used to study corrosion resistance in simulated seawater. Results showed that grain size and basal texture strength of pure Ti decreased after 2 ECAP passes, but the fraction of low angle grain boundary(LAGB) increased drastically. With increasing of extrusion passes, grain size and the fraction of LAGB decreased for samples, meanwhile, basal texture strength increased at first and then decreased.Electrochemical experiments indicated that all UFG titanium have better corrosion resistance than coarse one. On the other hand, it was founded that corrosion resistance didn’t increased monotonously with the development of ECAP passes, and 3 ECAP passes displayed optimum. This could be attributed to the interaction of grain size, basal texture and grain boundary character distribution, and basal texture strength occupied the domination.
作者
李鑫
董月成
淡振华
常辉
方志刚
郭艳华
LI Xin;DONG Yuecheng;DAN Zhenhua;CHANG Hui;FANG Zhigang;GUO Yanhua(College of Materials Science and Engineering/Tech Institute for Advanced Materials, Nanjing Tech University, Nanjing 211816, China;Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Nanjing Tech University, Nanjing 211816, China;State Key Laboratory of Metal Material for Marine Equipment and Application, Anshan 114000, China;Naval Research Institute, Beijing 100000, China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2019年第8期967-975,共9页
Acta Metallurgica Sinica
基金
国防基础科研计划项目No.JCKY08414C020
海洋装备用金属材料及其应用国家重点实验室开放基金项目No.SKLMEA-K201807
中国博士后科学基金面上项目No.2017M623392
江苏省研究生科研与实践创新计划项目No.SJCX19_0324
江苏高校优势学科建设工程资助项目~~
关键词
纯Ti
腐蚀性能
晶粒尺寸
织构
晶界特征分布
pure Ti
corrosion behavior
grain size
texture
grain boundary character distribution
