Microstructure and Evolution Behavior of Linear Friction Welded Joints of TA19 Titanium Alloy with Bimodal Structure

In this paper, the microstructure of linear friction welded joints of TA19 titanium alloy with bimodal structure was studied. Moreover, the defor-mation behaviors of the equiaxed primary α phase and the lamellar β transformation structure as well as the formation mechanism of the joint were analyzed. The results show that during linear friction welding, the severe and continuous thermoplastic deformation leads to a successive changing process of the bimodal structure, from structure coarsening, deformation, disintegration to a complete fragmentation, and ultimately it turns into the refined grain equiaxed structure. From heat-affected zone of welded joint to welded center, the equiaxed primary α phase undergoes discontinuous plastic deformation, fragmentation and eventually turns into β phase completely, while the lamellar β transformation structure expe-riences deformation, disintegration and ultimately a complete fragmentation. © 2020, Materials Review Magazine. All right reserved.