激光焊接铝基复合材料钛的原位增强作用

本文采用激光焊接SiC_p/6063铝基复合材料,并利用Ti对焊缝进行原位增强。研究结果表明,焊缝和热影响区均较窄,焊缝中观察不到孔洞存在。对焊缝中心的微观组织分析表明,焊缝基体的晶粒非常细小,呈等轴结晶方式,焊缝组织非常致密,没有明显的微观气孔和裂纹。焊缝中已经观察不到SiC颗粒与基体在熔焊条件下发生反应生成的针状反应物Al_4C_3,而是尺寸更为细小的TiC颗粒,近似呈球形,在焊缝中分布比较均匀。整个焊接区域转变为母材是SiC颗粒增强的Al基复合材料,而焊缝主要是以TiC颗粒增强相以Ti为基体的局部区域。研究结果表明,用钛作为合金化元素通过使用原位焊缝合金化/脉冲激光焊接SiC_p/6063复合材料可以达到完全抑制在焊缝中心区形成Al_4C_3,焊缝接头强度由于快速固化的TiC等相而得到提高。

In-situ Reinforcing Effect of Ti on Aluminum Matrix Composite during Laser Beam Welding

Laser beam welding was used to join SiCp/6063Al composite and Ti was used as in-situ material. The result showed that weld and HAZ are narrow and no pore can be found in weld. The analysis on microstructure of weld center showed that the grain size of weld matrix is very fine and the grains crystallize as equiax crystal, microstructure of weld is very compact and no obvious micro - gaspore and crack are found. No needlelike reaction product A14C3 is observed in weld, which can produce when SiC particles react with matrix during fusion welding. There are many finer TiC particles which are nearly round and the distribution of the particles is even in weld. The whole welding zone turns to be as follow: the base metal is SiC particles reinforced Al matrix composite and the weld is partial zone in which TiC particles are reinforcement and Ti is matrix. The result showed that A14C3 in weld center is restrained completely with Ti as in - situ' weld - alloying materials during impulsed laser beam welding for SiCp/6063 composite and the intensity of joint is increased due to rapidly solidified phases such as TiC.