INFLUENCE OF AGING PROCESS ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Ti6Al4V - Ti-CP WELDING ZONE

Abstract

TIG welding of two different titanium alloys Ti6Al4V and Ti-CP (ASTM Grade 2) with Ti6Al4V, conducting tensile test of welds in different states: after welding, heat treatment includes quenching and aging in several different modes, investigating the change about hardness and microstructure of the weldding zone. The microstructure results show that the weld element distribution in the alloy diffusion transition zone has a distance of (7÷8)µm, the characteristics of this zone almost do not change in size when heat treated. The results show that heat treatment has a negligible effect on weld strength but affects the elongation of alloy. The weld destruction mainly occurs in the vicinity of the weld in the heat-affected zone (HAZ) towards Ti-CP. Weldding samples of Ti-CP and Ti6Al4V when heat treated include quenching at 900^oC-2h, and curing at 525^oC for higher elongation compared to annealing and aging at temperatures of 400^oC and 650^oC.