铸态Ti-Sc二元合金的组织特征、相结构和显微硬度

Microstructure, phase structure and microhardness of as-cast Ti-Sc binary alloys

采用真空电弧熔炼技术制备了4种成分的Ti-Sc二元合金,并借助金相显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)技术及显微硬度测试,对合金的组织形貌、相成分以及不同形貌相的显微硬度进行了分析.结果表明:合金铸态组织形貌为螺旋状、团簇状片层、双相组织;金属Sc对合金的组织有着明显的细化作用,在合金中Sc与Ti形成了固溶体,不同形貌的相,其显微硬度差别较大;当Sc含量为2%～3%时,Ti-Sc二元合金的显微硬度达到最高值,Sc含量高于2%～3%时,合金基体硬度高于片层组织硬度,Sc含量低于2%～3%时,合金基体硬度低于片层组织硬度,少量Sc对合金性能有所提高,对α相片层组织有强化作用.

Four kinds of Ti-Sc binary alloys were prepared by vaccum arc melting technique. Microstructure, phase components and microhardness of different phases were analyzed by optical microscopy(OM), scanning electron microscope(SEM), X-ray diffraction(XRD) and microhardness tester. The results show that scandium plays a significant role on refinement of the microstructure. Solid solution forms in Ti-Sc binary alloys. The measured microhardness of different phases are in significant discrepancy. Microhardness of Ti-Sc binary alloys reaches the maximum value with 2%3% Sc. When Sc content is higher than 2%3%, microhardness of matrix is higher than that of plate-like phases, contrary tendency can be seen when Sc content is lower than 2%3%. Small content of scandium can improve the properties of alloys and strengthen the α plate-like phases.