摘要
The microstructure and mechanical properties of fine grained uranium prepared by equal channel angular pressing(ECAP)and subsequent intermediate heat treatment were investigated systematically by the confocal laser scanning microscope(CLSM),electron backscatter diffraction(EBSD)and split Hopkinson pressure bar(SHPB).The results show that the initial coarse grained uranium was refined from about 1000 to 6.5μm prepared by ECAP at 3 passes and subsequent heat treatment,and the corresponding dynamic yield strength increased from 135 to 390 MPa.For the ECAPed uranium samples,the relationship between grain size and yield strength could be described by classical Hall−Petch relationship,and the fitting Hall−Petch relationship for the fine grained uranium samples prepared by ECAP was drawn.
采用等通道挤压及热处理相结合的技术制备细晶金属铀,采用激光共聚焦显微镜、电子背散射衍射、霍普金森压杆系统地研究细晶金属铀的显微组织及力学性能。结果表明,粗晶金属铀经3道次等通道挤压及后续热处理后晶粒尺寸由约1000μm细化为6.5μm,相应的动态屈服强度由135 MPa增加至390 MPa。对于等通道挤压铀样品,用经典Hall−Petch公式能描述晶粒尺寸与屈服强度之间的关系,同时获得等通道挤压技术制备细晶金属铀的Hall−Petch拟合关系。
基金
Project(51401187)supported by the National Natural Science Foundation of China
Projects(2014B0301046,2015B0301066)supported by the Science Development Fund of China Academy of Engineering Physics。
