Reduction of hot cracking in laser welding using hypereutectic AlSi filler wire

Laser beam welding of aluminium alloys becomes increasingly important. However, in welding of high-strength aluminium alloys one main problem is hot cracking in the weld metal. Increasing the silicon content in the weld metal by introducing filler wire can reduce the occurrence of hot cracking. Today available filler wires are limited to 12 % Si since materials having higher Si content cannot be processed into wire. Spray forming is capable of producing hypereutectic Al-Si wires with a fine-grained microstructure in comparison with conventional cast alloys. In this investigation, the performance of spray formed AISi18 wire was compared to standard AISi12 wire. In view of process behaviour, no significant effect of the increased silicon content was observed. Furthermore, it was proven that the hot cracking susceptibility was decreased with increasing silicon content.