对3种包埋料铸出的钛铸件表面反应层的研究

Study on Surface Reaction Layer of Titanium Cast with Three Type Investments

目的:检测不同体系包埋料铸出的钛铸件表面反应层组成、显微结构及硬度变化。方法:分别用3种不同体系的包埋料包埋铸造钛铸件,肉眼观察铸件表面颜色;用电子探针对铸件表面反应层组成、显微结构进行分析;用显微硬度仪测试铸件表面硬度值。结果:氧化硅系、氧化铝系、氧化镁系包埋料铸出的钛铸件表面颜色分别是黑色、银灰色、橙黄色;表面反应层厚度分别是80μm、50μm、14μm;表面硬度结果显示:氧化硅系、氧化铝系、氧化镁系铸件分别在距表面120μm、80μm、40μm内硬度值明显减少,超出此范围变化较小;3种铸件表面硬度值在距表面120μm后趋于一致。结论:氧化硅系包埋料铸出的钛铸件表面反应层厚度最厚,反应最多;氧化镁系包埋料铸出的钛铸件表面反应层厚度最薄,反应最少;氧化铝系包埋料处入它们两者之间。从反应层的角度来看,氧化镁系包埋料是这3种包埋料中最理想的铸钛包埋料。

Objective： To study the composition, mierostrueture and mierohardness change of the surface reaction layer of titanium east with three investments. Methods： The eolour of Ti castings were seen by eyes. The mierostrueture in the reaction layer of Ti castings was observed by EPMA. And its mierohardness was measured by a mieroviekers hardness tester. Results ： The eolour of Ti castings east with SiO2, Al2O3 , and MgO investments was black, silver gray, and orange respectively. The thickness of surface reaction layers of Ti castings east with SiO2, Al2O3, and MgO investments was 80μm, 50μm, and 14μm, respectively. The surface hardness of titanium castings east with SiO2, Al2 O3 , and MgO investments all reduced greatly from the surface to underneath 120μm, 80μm, and 40μm, Their surface mierohardness of titanium castings was same when the depth from the surface was over 120μm, Conclusion： The surface reaction layer of titanium east with SiO2 investments is the biggest and it is the least in the titanium east with MgO investment. From the surface reaction layer we observed, MgO investments are the best investment among these three types investments.