학술논문
β/B2상을 포함한 Ti-Al-Mo-Nb 합금의 산화 거동과 실리콘 화합물 코팅을 통한 내산화성 개선
Document Type
Article
Source
대한금속·재료학회지 (2019): 131-137.
Subject
Language
Korean
ISSN
17388228
Abstract
Alloys containing the β/B2 phases of Ti-45Al-3Mo, Ti-45Al-3Mo-2Nb and Ti-45Al-5Mo were prepared using an vacuum arc-melting machine. Heat-treatments were carried out at 1250 oC in an Ar atmosphere. The temperature of 1250 oC is the temperature region of phase α + γ + (β/B2), and the heat treatment condition which improves mechanical properties by decreasing the fraction of the β/B2 phase. The presence of the β/B2 phase can result in relatively weakness at high temperatures and collapses the lamellar structure of the α2 / γ phase during heat treatment. The transient oxidation behaviors of Ti-45Al-(3, 5)Mo-(2Nb) (at%) alloys were investigated in an ambient atmosphere at 900 and 1000 oC. Initial oxidation behaviors and oxidation resistance of the three alloys were compared at 1000 oC. The oxidation resistance of the Ti-45Al- 3Mo-2Nb alloy containing Mo and Nb was the most remarkable among the three alloys at 900 oC and 1000 °C. At the same time, Si pack cementation coated Ti-45Al-3Mo-2Nb alloys and oxidation behavior were also analyzed. The phase sequences of the multilayers of τ2 / Ti5Si4 / TiAl3 / TiAl2 /TiAl were observed on the substrate. Also, a diffusion pathway of the silicide coating layers in the ternary phase diagram of Ti-Al-Si was proposed. The oxidation resistance of the silicide coated TiAl alloys was improved during the oxidation tests at 1000 oC.
Alloys containing the β/B2 phases of Ti-45Al-3Mo, Ti-45Al-3Mo-2Nb and Ti-45Al-5Mo were prepared using an vacuum arc-melting machine. Heat-treatments were carried out at 1250 oC in an Ar atmosphere. The temperature of 1250 oC is the temperature region of phase α + γ + (β/B2), and the heat treatment condition which improves mechanical properties by decreasing the fraction of the β/B2 phase. The presence of the β/B2 phase can result in relatively weakness at high temperatures and collapses the lamellar structure of the α2 / γ phase during heat treatment. The transient oxidation behaviors of Ti-45Al-(3, 5)Mo-(2Nb) (at%) alloys were investigated in an ambient atmosphere at 900 and 1000 oC. Initial oxidation behaviors and oxidation resistance of the three alloys were compared at 1000 oC. The oxidation resistance of the Ti-45Al- 3Mo-2Nb alloy containing Mo and Nb was the most remarkable among the three alloys at 900 oC and 1000 °C. At the same time, Si pack cementation coated Ti-45Al-3Mo-2Nb alloys and oxidation behavior were also analyzed. The phase sequences of the multilayers of τ2 / Ti5Si4 / TiAl3 / TiAl2 /TiAl were observed on the substrate. Also, a diffusion pathway of the silicide coating layers in the ternary phase diagram of Ti-Al-Si was proposed. The oxidation resistance of the silicide coated TiAl alloys was improved during the oxidation tests at 1000 oC.
Alloys containing the β/B2 phases of Ti-45Al-3Mo, Ti-45Al-3Mo-2Nb and Ti-45Al-5Mo were prepared using an vacuum arc-melting machine. Heat-treatments were carried out at 1250 oC in an Ar atmosphere. The temperature of 1250 oC is the temperature region of phase α + γ + (β/B2), and the heat treatment condition which improves mechanical properties by decreasing the fraction of the β/B2 phase. The presence of the β/B2 phase can result in relatively weakness at high temperatures and collapses the lamellar structure of the α2 / γ phase during heat treatment. The transient oxidation behaviors of Ti-45Al-(3, 5)Mo-(2Nb) (at%) alloys were investigated in an ambient atmosphere at 900 and 1000 oC. Initial oxidation behaviors and oxidation resistance of the three alloys were compared at 1000 oC. The oxidation resistance of the Ti-45Al- 3Mo-2Nb alloy containing Mo and Nb was the most remarkable among the three alloys at 900 oC and 1000 °C. At the same time, Si pack cementation coated Ti-45Al-3Mo-2Nb alloys and oxidation behavior were also analyzed. The phase sequences of the multilayers of τ2 / Ti5Si4 / TiAl3 / TiAl2 /TiAl were observed on the substrate. Also, a diffusion pathway of the silicide coating layers in the ternary phase diagram of Ti-Al-Si was proposed. The oxidation resistance of the silicide coated TiAl alloys was improved during the oxidation tests at 1000 oC.