连铸Ag-28Cu-0.75Ni合金相组成、组织及性能

发布时间：2018-07-14 18:09

【摘要】：采用连续铸造技术制备Ag-28Cu-0.75Ni(%,原子分数)合金棒材,真空退火后进行冷拉拔加工,分别采用X射线衍射(XRD)、金相显微镜(OM)和扫描电镜(SEM)对合金的物相、铸态、加工态和断口组织进行表征,并对导电率、硬度、强度和延伸率进行测试。结果表明:Ag-28Cu-0.75Ni的显微组织为:以Ag,Ni为溶质的Cu相固溶体,以Cu为溶质的Ag相固溶体和共晶(Ag+Cu)结构;其连铸态微观结构为典型的表面细晶区、柱状晶区和中心等轴层片状晶区三区结构,铸锭中散落着形貌清晰、形态规整的枝晶,枝晶偏析以及中心等轴区的边界偏析造成易腐蚀的低熔点区域。同时,材料本身加工态横截面晶粒细化、组织均匀,纵截面晶粒由点块状变为纤维状,发生择优取向形成形变织构。随真应变的增加,强度、硬度随之增加,而导电率、延伸率下降。
[Abstract]:Ag-28Cu-0.75Ni alloy bar was prepared by continuous casting technique. The alloy was cold drawn after vacuum annealing. The phase of the alloy was studied by X-ray diffraction (XRD), metallographic microscope (OM) and scanning electron microscope (SEM). The machined and fracture microstructures were characterized, and the electrical conductivity, hardness, strength and elongation were measured. The results show that the microstructures of W Ag-28Cu-0.75Ni are Cu solid solution, Cu solid solution and eutectic (Ag Cu) structure, and the microstructures of Ag phase and eutectic (Ag Cu) in continuous casting are typical surface fine crystalline region. The structure of columnar and central equiaxial lamellar crystal region is three regions. The morphology of the ingot is clear and the dendritic segregation and the boundary segregation of the central equiaxed region lead to the low melting point region which is easy to be corroded. At the same time, the grain size of the cross section of the material itself is fine, the microstructure is uniform, the grain of the longitudinal section is changed from point block to fibrous, and the preferred orientation forms deformation texture. With the increase of true strain, the strength and hardness increase, while the conductivity and elongation decrease.
【作者单位】：昆明贵金属研究所稀贵金属综合利用新技术国家重点实验室;
【基金】：国家自然科学基金项目(51267007) 云南省院所技术开发专项(2013DC016) 云南省院省校科技合作项目(2015IB012) 院士专家工作站项目(2015IC046)资助
【分类号】：TG146.32;TG293

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