TC11钛合金线性摩擦焊界面微观组织演变

Microstructural Evolution of TC11 Titanium Alloy at Rubbing Interface During Linear Friction Welding

为了探明TC11钛合金线性摩擦焊过程中界面金属微观组织演变规律,采用光学显微镜和扫描电镜来研究飞边与接头的微观组织。结果表明,线性摩擦焊界面演变过程可依次分为摩擦磨损、黏着剪切、界面金属形成金属键连接并发生大变形、动态再结晶四个阶段。当摩擦时间足够长时,整个摩擦界面温度趋于均匀,在界面上将形成一层厚度均匀的塑性金属层,α相完全转变为β相,并且初生β相晶粒将发生动态再结晶过程。随着摩擦时间的延长,界面温度升高,初生β相动态再结晶晶粒尺寸增大。

Microstructure of flash and joint was investigated using optical microscopy （OPM） and scanning electron microscopy （SEM） for understanding microstructure evolution of TCll titanium al loy at the rubbing interface during linear friction welding. The results show that microstructure evolu tion of titanium alloy at the rubbing interface during linear friction welding contained four stages, that is, sliding friction and wearing, sticking and shearing friction, forming metallic bond and having a highly deformed microstructure, dynamic recrystallization in sequence. Temperature was uniform at the rubbing interface for sufficient friction time, and plastically deformed material was formed. That resulted in complete transformation of alpha to beta phase and then dynamic recrystallization of prior beta phase. The dynamic recrystallization grain size of prior beta phase would be greater with friction time rising due to higher temperature.