采用线性摩擦焊焊接TC4钛合金, 对焊态下接头的显微组织及硬度进行了分析与测试。结果表明: 焊接接头可分为母材区、热机影响区和焊核区。热机影响区组织由母材至焊核区依次为等轴α相和层片状(α+β)相沿受力方向被拉长组织、纤维状组织中伴有等轴状α和层片状(α+β)再结晶晶粒、针状α′和少量的α再结晶组织。焊核区组织为针状α′, 而且纵向由中心至边缘组织逐渐粗大。垂直于焊缝方向由母材过渡到焊缝中心硬度逐渐由360 HV增大到390 HV左右, 焊核区纵向硬度由中心向边缘逐渐减小到330 HV左右。

TC4 alloy was welded by linear friction welding process. Microstructure of the joint was analyzed, and microhardness distribution of the joint was tested. The results showed that the welded joint can be divided into three zones: base metal zone, thermo affect zone (TMAZ) and weld zone. The microstructure of TMAZ are consist of equiaxed α and lamellar (α+β) be elongated in forced direction, fibrous and recrystallized(α and β) microstructure, acicular α′ and a little recrystallized α from near base metal to weld center. The microstructure at the weld zone is acicular α′. The size of α′ gradually becomes thicker from center to edge. The microhardness gradually increases from about 360 HV to 390 HV from the center to base metal in the direction perpendicular to the weld seam. Longitudinal microhardness of the weld zone gradually reduces to about 330 HV from the center to edge.