中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 34 No. 8 August 2024 |
（1. School of Materials Science and Engineering, East China Jiaotong University, Nanchang 330013, China;
2. State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure, East China Jiaotong University, Nanchang 330013, China;
3. National Engineering Research Center of Near-net-shape Forming for Metallic Materials, South China University of Technology, Guangzhou 510640, China）
Abstract:A novel micro-nano Ti-10Cu-10Ni-8Al-8Nb-4Zr-1.5Hf filler was used to vacuum braze Ti-47Al- 2Nb-2Cr-0.15B alloy at 1160-1220 °C for 30 min. The interfacial microstructure and formation mechanism of TiAl joints and the relationships among brazing temperature, interfacial microstructure and joint strength were emphatically investigated. Results show that the TiAl joints brazed at 1160 and 1180 °C possess three interfacial layers and mainly consist of α2-Ti3Al, τ3-Al3NiTi2 and Ti2Ni, but the brazing seams are no longer layered and Ti2Ni is completely replaced by the uniformly distributed τ3-Al3NiTi2 at 1200 and 1220 °C due to the destruction of α2-Ti3Al barrier layer. This transformation at 1200 °C obviously improves the tensile strength of the joint and obtains a maximum of 343 MPa. Notably, the outward diffusion of Al atoms from the dissolution of TiAl substrate dominates the microstructure evolution and tensile strength of the TiAl joint at different brazing temperatures.
Key words: γ-TiAl alloy; micro-nano filler; vacuum brazing; interfacial microstructure; tensile strength
