Cu-Cr-Zr合金连续驱动摩擦焊接头热力演变

Thermo-mechanical evolution of Cu-Cr-Zr alloy joint fabricated by continuous driving friction welding

关键词:  Cu-Cr-Zr合金  连续驱动摩擦焊  接头温度  显微组织

Key words:  Cu-Cr-Zr alloy  continuous drive friction welding (CDFW)  joint temperature  microstructure

摘要:

采用热电偶—蓝牙技术测量了Cu-Cr-Zr合金连续驱动摩擦焊接头特征点的温度,并研究接头温度与组织演变的关系. 结果表明,各特征点温度均存在一定程度的滞后现象;沿工件径向, 2/3R区温度最高;沿工件轴向,摩擦界面处温度最高;旋转工件的温度略低于移动工件. 在热力耦合作用下,接头焊合区形成细小的等轴晶粒,热力影响区晶粒被不同程度拉长,呈塑性流线.从轴心到外径动态再结晶区的宽度增加,晶粒粗化,而与其相邻的热力影响区径向塑性流动的趋势减小. 此外,与旋转端相比,移动端接头具有较高的峰值温度和再结晶峰值宽度,所对应的焊合区晶粒也较为粗大.

Abstract:

The thermocouple-bluetooth technology was employed to measure temperatures at feature points of Cu-Cr-Zr alloy joint fabricated by continuous drive friction welding. The relationship between temperature and microstructure evolution of welded joint was also investigated. The results show that every feature point demonstrated a certain temperature delay phenomenon. The highest temperature occurred in two-thirds radius area along the radial direction, and at friction interface along the axial direction, respectively. Meanwhile, the temperature in rotary workpiece was lower than that in moving workpiece. Due to the effect of thermo-mechanical coupling, fine equiaxed grains formed in the weld nugget zone while the grains in thermal-mechanical affected zone (TMAZ) were elongated with obvious plastic flow. From axis to outside diameter, both the width of dynamic recrystallization area and grain size increased while the trend of radial plastic flow in adjacent TMAZ decreased. In addition, compared with rotary workpiece, grains in the weld zone of [HJ1.55mm]moving workpiece became coarsened due to higher temperature and longer duration over recrystallization temperature.