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使用冷壁坩埚真空感应炉熔炼及金属模铸造方法,制备了Ti-8.15Si合金。利用光学显微镜、XRD、SEM、多功能试验机等技术,研究了合金的凝固组织特点、热处理对组织形貌的影响及抗压性能。结果表明,Ti-8.15Si合金可以获得αTi和Ti5Si3化合物形成的共晶组织,初生Ti5Si3相为比较粗大的棒状,共晶Ti5Si3相为细小的枝状或棒状,横断面呈六角形结构。1323K保温60min热处理使粗大棒状的Ti5Si3相显著减小;枝状Ti5Si3相变成非连续的、细小的粒状形态,改进了抗压综合性能。保温120minTi5Si3相逐渐长大,并且有少量块状的Ti3Si相生成,保温时间延长到180min,Ti3Si相数量明显增多,材料的硬度和抗压强度增加,塑性降低。
Ti-8.15Si alloy was prepared by cold-crucible vacuum induction furnace melting and metal mold casting. The characteristics of the solidified microstructure, the effect of heat treatment on the microstructure and the compressive strength of the alloy were studied by means of optical microscope, XRD, SEM and multi-function testing machine. The results show that the eutectic structure of αTi and Ti5Si3 compounds can be obtained by Ti-8.15Si alloy. The primary Ti5Si3 phase is coarser rod shape. The eutectic Ti5Si3 phase is finely dendritic or rod shape with a hexagonal cross section. Heat treatment at 1323K for 60min significantly reduced the coarse rod-shaped Ti5Si3 phase; the dendritic Ti5Si3 phase transformed into a discontinuous and fine granular morphology, improving the compressive properties. The phase of 120minTi5Si3 grows gradually, and a small amount of massive Ti3Si phase is formed. When the holding time is prolonged to 180min, the amount of Ti3Si phase obviously increases, the hardness and compressive strength of the material increase and the plasticity decreases.