Effect of Gradient Layer Number on Microstructure and Property of Laser Deposition TA15/Ti₂AlNb Transition Zone

Abstract

3 numerical models of laser deposited TA15/Ti2AlNb gradient composite structure were established to simulate the temperature variation of gradient composite structures with different gradient layers in different regions. Then TA15/Ti2AlNb gradient composite structures with different gradient layers were prepared by laser deposition technology. The microstructure, room-temperature tensile properties and microhardness of the deposited samples were observed by optical microscope, tensile testing machine, scanning electron microscope and microhardness tester. The results showed that as the number of gradient layers increased, the temperature in the deposition process of the transition zone increased, while the microstructure difference in the transition zone decreased gradually. As the number of transition layers increased, the tensile strength decreased, but the elongation after fracture increased. All the fracture locations were in the transition zone, and with the increasing of gradient layers, the fracture location gradually shifted to the Ti2AlNb side. The microhardness of the transition zone increased with the increasing of gradient layers. This study will provide reference for the optimization design of TA15/Ti2AlNb gradient composite structure.