Microstructure and mechanical properties of TIG welded-brazed joint of pre-coating titanium and aluminum alloy

The titanium alloy plate was hot-dipped pure aluminum coating by the position of groove, then the pre-coating titanium alloy was joined to aluminum alloy by TIG welding-brazing. Comparison was made between the uncoated and coated joint to analyze interfacial structure and the strength of weld seam. The test results showed that, the same component TiAl₃ formed under two kinds of interface conditions. There is a interface reaction layer with the thickness of 4~6 μm in the non-coating joint, and the average tensile strength of the joint is 11 8 MPa, brittle fracture is the main fracture mode in tensile test. And the pre-coating joint has the interface reaction layer with the thickness of 2 μm, the average tensile strength of the joint is 205 MPa, and the fracture mode is ductile fracture. The introduction of coating can make the intermetallic compound layer thinner and the fracture mode be changed.