논문 해외 국제전문학술지(SCI급) Microstructural Evolution in Cast and HIP'ed Ingot Material of Beta Gamma TiAl Alloy by Two Step Cooling
- 학술지 구분 국제전문학술지(SCI급)
- 게재년월 2018-05
- 저자명 박준식,김정민공동(참여),최광수,김영원
- 학술지명 KOREAN JOURNAL OF METALS AND MATERIALS
- 발행처명 KOREAN INST METALS MATERIALS
- 발행국가 해외
- 논문언어 외국어
홈페이지논문 초록 (Abstract)
The beta gamma alloys of Ti - 43.8Al - 4Nb - 2Cr - 0.2B - 0.2C at % (9CN) were prepared using induction skull melted (ISM) cast ingots. In order to make a fine fully lamellar structure with some minor phases, two step cooling was performed using two furnaces after heat treatments in the α + β phase region. The heat-treatments produced an ~50 μm fully lamellar structure with α2 / γ + γ + B2 (HIP) → α + β (heating) → α / γ (FL) + γ + B2 → α2 / γ (FL) + γ + B2 phase change. For the two step heat treatment, the specimen was heat treated at 1340 oC(or 1350 oC) and transferred to another furnace, which was maintained at 950 oC, in order to minimize any phase transformations between the temperatures. Fully lamellar specimens with some phases were compression-tested at RT, 700 oC, 800 oC, 900 oC and 1000 oC, and showed excellent compressive strength at high temperature. The resultant material property determined via this cooling process was superior to that of other materials such as Ni based superalloys or commercial TiAl alloys. The microstructures associated with the cooling effect were discussed in terms of materials properties and phase transformation.