NiTiNb/TC4异种材料激光微焊接头裂纹研究

Study on Crack Sensitivity of NiTiNb/TC4 Laser Micro-welding Joints

NiTiNb/TC4异种材料激光焊时,焊接接头的裂纹敏感性很强,在较小激光功率时,焊缝就出现了裂纹,通过改变激光功率无法消除接头裂纹。通过填加Ti丝来调节接头中Ti的含量来减小Ti2Ni的生成,从而控制接头裂纹的生成。研究表明,当加入Ti丝后,在不同激光功率下,接头成形良好,焊缝中存在微细裂纹;在NiTiNb侧存在宽10μm的Ti2Ni过渡区,TC4侧结合良好;当激光频率为3Hz、激光脉宽为4.5ms、激光平均功率为13.6W时,接头最大抗拉强度达447MPa。

When the NiTiNb / TC4 dissimilar material is welded by laser, the crack sensitivity of the welded joint is very strong. Weld cracks appeared even at low laser power. Changing the laser power can not eliminate the joint crack. The formation of Ti2Ni was controlled by adding the Ti wire to adjust the content of Ti in the joint, so as to control the formation of the joint crack. Research showed, when the Ti wire was added, the joint was formed well under different laser power, and the micro cracks exist in the weldo There was a width 10pm Ti2Ni transition regions on the NiTiNb side, and the TC4 side was well bonded. When the laser frequency was 3Hz, the laser pulse width was 4.Sms and the laser average power was 13.6W, the maximum tensile strength of the joint was 447MPa.