Brazeability evaluation of Ti-Zr-Cu-Ni-Co-Mo filler for vacuum brazing TiAl-based alloy
(1. School of Materials Science and Engineering, East China Jiaotong University, Nanchang 330013, China;
2. National Engineering Research Center of Near-net-shape Forming for Metallic Materials, South China University of Technology, Guangzhou 510640, China;
3. National Engineering Research Center of Powder Metallurgy of Titanium & Rare Metals, Guangdong Institute of Materials and Processing, Guangzhou 510650, China)
2. National Engineering Research Center of Near-net-shape Forming for Metallic Materials, South China University of Technology, Guangzhou 510640, China;
3. National Engineering Research Center of Powder Metallurgy of Titanium & Rare Metals, Guangdong Institute of Materials and Processing, Guangzhou 510650, China)
Abstract: Ti-47Al-2Nb-2Cr-0.15B (mole fraction, %) alloy was vacuum brazed with amorphous and crystalline Ti-25Zr- 12.5Cu-12.5Ni-3.0Co-2.0Mo (mass fraction, %) filler alloys, and the melting, spreading and gap filling behaviors of the amorphous and crystalline filler alloys as well as the joints brazed with them were investigated in details. Results showed that the amorphous filler alloy possessed narrower melting temperature interval, lower liquidus temperature and melting active energy compared with the crystalline filler alloy, and it also exhibited better brazeability on the surface of the Ti-47Al-2Nb-2Cr-0.15B alloy. The TiAl joints brazed with crystalline and amorphous filler alloys were composed of two interfacial reaction layers and a central brazed layer. Under the same conditions, the tensile strength of the joint brazed with the amorphous filler alloy was always higher than that with the crystalline filler alloy. The maxmium tensile strength of the joint brazed at 1273 K with the amorphous filler alloy reached 254 MPa.
Key words: vacuum brazing; Ti-47Al-2Nb-2Cr-0.15B alloy; amorphous Ti-25Zr-12.5Cu-12.5Ni-3.0Co-2.0Mo filler alloy; tensile strength; interfacial microstructure; brazeability