2种冷速真空吸铸Ti-48Al合金的组织性能研究

Research on Microstructure and Property of TiAl Alloys with Common and Quick Cooling Suction Casting

利用磁悬浮感应熔炼和真空吸铸技术对Ti-48Al合金进行普通吸铸和快冷吸铸。利用维氏硬度计进行显微硬度测试,采用光学显微镜和扫描电镜进行晶粒尺寸和微观组织观察。结果表明,2种吸铸方式制备的Ti-48Al合金微观组织区别在于晶粒尺寸的大小,快冷吸铸Ti-48Al合金晶粒明显细化,晶粒尺寸为普通吸铸合金的1/10～1/2;相比普通吸铸,快冷吸铸Ti-48Al合金晶粒生长具有更强的择优取向,主要沿(111)‖(0002)α2晶向择优生长;快冷吸铸显微硬度为483.73HV,比普通吸铸Ti-48Al合金(显微硬度为260.49HV)提高了85.7%;而且快冷吸铸Ti-48Al合金由于晶粒细化还显著增强了Ti-48Al合金的室温塑性。

In this paper, Ti-48A1 was fabricated by using the technology of magnetic levitation induction melting and vac- uum suction casting. Vickers hardness tester were used to test the micro-hardness of Ti-48A1 with two different suction castings and optical microscope （OM） and scanning electron microscope （SEM） were utilized to characterize the rnicrostruc ture and phases micromorphology. As a result, they almost doesn＇t have any other difference on the microstructure except the grain size, and the alloy prepared by quick cooling suction casting has a great smaller grains than that of other ones, only 1/10 tol/2. The hardness of Ti-48A1 alloys with common and quick suction casting reached about 260.49 and 483.73 HV separately. Furthermore, it is significant for Ti-48AI alloy that improving cooling speed is good for enhancing its room tern perature plasticity.