TA19双态组织钛合金线性摩擦焊接头的组织结构及演化行为

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

本实验研究了具有双态组织结构特征的TA19钛合金线性摩擦焊接头的组织结构,分析了等轴初生α相和片层结构β转变组织的变形行为及接头焊缝的形成机制。结果表明:线性摩擦焊接时剧烈的连续热塑性变形使得焊缝中心的TA19双态组织钛合金经历了组织粗化、变形、破碎以及完全碎化的过程,最终转变为超细晶等轴组织。从焊接接头的热影响区到焊缝中心,等轴初生α相经历了不连续的塑性变形和破碎最终完全相变为β相。片层结构β转变组织则先后经历了变形、解体并完全碎化的过程。

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 primaryαphase and the lamellarβtransformation 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 primaryαphase undergoes discontinuous plastic deformation,fragmentation and eventually turns intoβphase completely,while the lamellarβtransformation structure expe-riences deformation,disintegration and ultimately a complete fragmentation.