摘要
本研究通过等径通道挤压(ECAP)对孪晶诱导塑性变形钢(TWIP钢)在300℃下进行了晶粒细化,并运用金相显微镜、电子背散射衍射(EBSD)、透射电镜(TEM)观察了经不同道次挤压后TWIP钢的晶粒、孪晶形貌及位错组织。结果表明,在均匀化退火状态下,试样晶粒基本呈现等轴状态,通过测微尺测量晶粒尺寸,约为(90±30)μm。在1道次挤压后,晶粒沿剪切方向显著伸长,并有尺寸较小的新晶粒产生,许多形变孪晶在剪切带中产生。2道次挤压后新产生的细小晶粒增多,并开始产生许多微孪晶,孪晶易于在晶界处产生。经过4道次等径通道挤压,晶粒逐渐细化至超细晶状态,晶粒尺寸达到0.3~1μm,孪晶厚度随挤压道次的增多而不断减小,甚至达到几十纳米。在不同晶粒尺寸下,TWIP钢在高温ECAP过程中产生孪晶的机理不同。
In the present study,grain refinement had been imposed on a TWIP steel by equal channel angular pressing（ECAP）at 300 ℃,and the grain microstructure,twins and dislocation morphology was detected by optical microscope,electron backscattered diffraction（EBSD）,and transmission electronic microscope（TEM）.It was found that in homogenized annealing condition,the specimen shows nearly equiaxed grain state,and the grain size is about（90±30）μm measured by micrometer.After the first pass of ECAP process,the grains are elongated in shear direction,along with the formation of new fine grains.Furthermore,numerous deformation twins are formed in shear band.In the 2 passes samples,more new fine grains are formed,as well as fine twins.The deformation twins tend to form near grain boundaries.After the fourth pass of ECAP,the microstructure reaches ultrafine state,and the grain size is about 0.3—1μm.The twin scale reduces with increasing number of ECAP pass,even reaches tens nanometers.In different scale of grain size,formation mechanism of twins in warm temperature ECAP process is different.
作者
王雷
奚运涛
王世清
高倩
WANG Lei, XI Yuntao, WANG Shiqing, GAO Qian(School of Materials Science and Engineering, Xi＇an Shiyou University, Xi＇an 71006)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2018年第A01期432-438,共7页
Materials Reports
基金
国家自然科学基金(51505379)
陕西省教育厅项目(16JK1615)
西安石油大学"材料科学与工程"省级优势学科资助
