With changing amplitude, the dissimilar titanium alloys of TC11 and TC17 were welded by linear friction welding and the welded joint temperature was measured. The microstructure of the joints and flash were examined using an optical microscope (OPM) and a scanning electron microscope (SEM). Electron probe microanalysis (EPMA) was also carried out to determine the elemental diffusion in and around the interface region. The results showed that with increasing amplitude, the weld heat input increased and the flash length increased. During the linear friction welding, the temperature around the interface exceeded 1100℃,above βtransition temperature. Dynamic recrystallization is operative on weld center and the flash during linear friction welding. There still exists an evident interface after welding and no mechanical mixture was found at the interface. Compared to the parent material, the microstructure in the weld and flash center was refined. The size of the recrystal grain on both sides of the welded joints decreased with increasing amplitude. Elemental diffusion layers exist on the interface and with the amplitude increased the thickness of the diffusion layer become wider.%通过改变振幅对TC11/TC17异质钛合金进行了线性摩擦焊及测温实验.焊后利用光学显微镜、扫描电镜及电子探针分析仪等对飞边、焊接接头微观组织及焊缝界面近域原子浓度进行了分析.结果表明,振幅越大,界面获得的焊接热输入越大,形成的飞边越大.线性摩擦焊接过程中焊缝组织温度超过1100℃,超过β相变温度.飞边组织发生明显的再结晶,界面依然存在且没有发生明显的机械混合.焊缝组织为再结晶组织,再结晶晶粒尺寸随振幅的减小而减小,焊缝中心存在明显的界面,界面处存在扩散过渡区,扩散层厚度随振幅的减小而变窄.
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