Spark Plasma Sintering for high-speed diffusion welding of the ultrafine grained near-a Ti-5Al-2V alloy with high strength and corrosion resistance for nuclear engineering

Abstract

The paper demonstrates the prospects of Spark Plasma Sintering (SPS) for the high-speed diffusion welding of the high-strength ultrafine-grained (UFG) near-a Ti-5Al-2V alloy. The effect of increased diffusion welding intensity in the UFG Ti alloys is discussed also. The welds of the UFG near-a-Ti-5Al-2V alloy obtained by SPS are featured by high density, strength, and corrosion resistance. The rate of weld sealing in the UFG alloys has been shown to depend on the heating rate non-monotonously (with a pronounced maximum). At the stage of continuous heating and isothermic holding, the kinetics of the weld sealing was found to be determined by the exponential creep rate, the intensity of which in the coarse-grained (CG) alloys is limited by the diffusion rate in the crystal lattice whereas in the UFG alloys it is limited by the grain boundary diffusion rate.