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Research on Filler Design and Interface Microstructure for Brazing γ–TiAl Alloys |
JING Yongjuan1, LIU Ye2, SHANG Yonglai1, LI Sisi1, ZHANG Yuanwei1 |
1. AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China;
2. China North Engine Research Institute, Tianjin 300400, China |
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Abstract γ–TiAl alloy is a kind of intermetallic compound material with great application potential. It was brazed by the designed filler as Ti–15.6Zr–11.0Cu–9.8Ni (mass fraction, %). The microstructure and element distribution of the joint were analyzed. The microhardness and strength of the joint were tested. It was found that the diffusion of Al to the interface was the main driving force for the formation of the interface. The Zr, Cu and Ni elements in the filler metal are mainly concentrated in the center of the adjacent interface. Due to the coarse grain structure and the high hardness of the grid structure, brazing fracture happened in the central part of the adjacent interface. Although there is a continuous Ti3Al phase near the interface, its excellent plasticity and the moderate hardness were beneficial to transfer the force between the matrix and the interface. Thus this phase was benefit for the toughness of the joint. The tensile strength of joint reaches to 517 MPa at room temperature, and the strength coefficient is 0.816。
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