Ti/Al异种合金激光熔钎焊过程气孔形成机制

Formation Mechanism of Porosity in Laser Welding-Brazing of Ti/Al Dissimilar Alloys

摘要:

采用矩形光斑CO2激光为热源，以AlSi12作为填充焊丝进行钛/铝异种合金的激光熔钎焊试验，发现气孔是导致接头失效的一个主要因素。结果表明，钛/铝异种合金激光熔钎焊的气孔缺陷主要是由镁元素的气化所致。光束的偏移量及激光功率是影响气孔产生的主要因素。界面棒状的金属间化合物长度低于10 μm时一般不产生气孔，而气孔的直径与焊缝内部的微观组织有关。

Abstract:

The laser welding-brazing experiment of Ti/Al dissimilar alloys was performed with rectangular spot CO2 laser as heat resource and AlSi12 as the filler wire. It is found that the porosity in the seam is a main factor for weak joint. The results indicate that the gasification of element Mg causes the formation of porosity during the welding. The offset of the laser beam toward Ti alloy and heat input markedly influence the formation of the porosity. In general no porosity is observed in the seam when the length of claviform intermetallic compound is less than 10 μm. Moreover, the microstructure in the seam plays a key role in the diameter of the pore.