Interface metallurgical control of laser melting deposited titanium alloy-nickel-based superalloy dissimilar material

Abstract

The titanium alloy-superalloy dissimilar material composite structure can give full play to the respective advantages of the two materials and achieve complementary performance, which has important application prospects in the field of aeroengine manufacturing. In this paper, the (V-15Cr)+0Cr13 intermediate layer structure was designed for TC4-GH4169 composite structure, and was prepared by laser melting deposition technology. The effects of the laser power and the powder stacking method on the metallurgical quality of the interface of the laser melting deposited TC4-GH4169 dissimilar material were studied. The results show that the interface metallurgical control of the (V-15Cr)+0Cr13 composite interlayer is a key factor affecting the metallurgical quality of TC4-GH4169. For the powder feeding laser melting deposition process, when the laser power is 400 W, there is no effective metallurgical reaction between 0Cr13 and V-15Cr due to the low laser energy, resulting in interlayer peeling; when the laser power is 600 W, a small amount of brittle σ phase appears at the interface of (V-15Cr)/0Cr13; when the laser power is increased to 800 W, there is a greater dilution ratio between the 0Cr13 and V-15Cr cladding layers, and the continuously distributed σ phase with a thickness of about 20 μm is formed at the interface. By using powder presetting laser melting deposition process and focusing the laser on the surface of the V-15Cr layer, the dilution ratio between the 0Cr13 and V-15Cr cladding layers can be controlled at a reasonable level, the formation of the σ phase at the interface can be effectively avoided. The shear test results show that the fracture occurs in the V-15Cr alloy layer. The interfacial strength reaches 299 MPa and the strength coefficient reaches 0.61.