Elevated Temperature Mechanical Properties and Fracture Failure Behavior of TC4-DT Alloy Deposited by Micro-Rolled Wire-arc Additive Manufacturing

The elevated temperature mechanical properties and fracture failure behavior of TC4-DT alloy deposited by micro-rolled wire-arc additive manufacturing were investigated. The phase composition and microstructure of TC4-DT alloy was observed in the direction of parallel and perpendicular to the deposition direction based on X-ray diffraction, Optical Microscope and Scanning Electron Microscope.The elevated temperature mechanical properties of TC4-DT alloys at different temperatures (500 ℃, 600 ℃and 700 ℃) were tested, and the tensile morphologies of the tensile fracture at different test temperatures were observed and the fracture failure behavior was analyzed. The results show that the main phase is α phase, the microstructure of TC4-DT alloy parallel and perpendicular to the deposition direction is basket-weave and α lamellar, suggesting no obvious anisotropy.As the temperature increases, the strength of TC4-DT alloy decreases, the fracture behavior is transformed from intergranular to transgranular at elevated temperature.The predominant factors affecting material fracture behavior include grain growth, softening of grain boundaries, growth and aggregation of pores at elevated temperatures.