AA6013铝合金光纤激光焊凝固裂纹影响因子研究

Research on impact factors of solidification crack of AA6013 aluminum alloy by fiber laser welding

凝固裂纹是汽车用铝合金AA6013在激光焊过程中极易形成的一种焊接缺陷。为了提高焊接质量,文中对AA6013铝合金高功率光纤激光焊时的凝固裂纹影响因子开展了系统研究。通过分析激光功率、焊接速度、焊缝位置等不同影响因子下的凝固裂纹敏感性,利用响应面优化法的Box-Behnken Design (BBD)建立了裂纹率与影响因子关系的相应模型,获得了关键参量,从而能够有效控制凝固裂纹的萌生。最后,利用光学显微镜和扫描电子显微镜对凝固裂纹的形貌特征进行了观察,发现Al与Mg2Si, Al2Cu形成的低熔点共晶体是6013铝合金焊接凝固裂纹产生的冶金因素。本研究结果可为抑制铝合金光纤激光焊过程中的凝固裂纹提供试验依据。

Solidification crack is one of the common welding defects in the laser welding of AA6013 aluminum alloy.To improve the welding quality,the sensitivity factors of AA6013 aluminum alloy in high power fiber laser welding was investigated in this paper.Solidification crack sensitivity was analyzed under different conditions including laser power,welding velocity and weld position by using Box-Behnken Design(BBD)to set up a model between crack rate and influencing factors.As a result,key parameters were attained to help control the initiation of solidification crack.Besides,optical microscopy(OM)and scanning electron microscopy(SEM)were used to analyze the crack surface and fracture morphology.It was noted that solidification crack in AA6013 aluminum alloy was caused by the fracture of intergranular liquid film.The research results provided experimental evidence to prevent solidification crack during the process of fiber laser welding of AA6013 aluminum alloy.