Micro laser metal wire deposition of thin-walled Al alloy components: Process and material characterization

In this work, micro laser metal wire deposition (mu LMWD) of 0.4 mm diameter 4047 Al-alloy (AlSi12) wire is demonstrated. A flash-pumped Nd:YAG laser producing ms-long pulses was used as the energy source. The processing conditions were studied for single and multi-layered tracks, seeking stable deposition conditions. Microhardness, microstructure and chemical composition were analysed. The results showed that thin walls with sub-mm thickness free of pores and cracks could be obtained using the mu LMWD process. The material was characterized by a homogenous microhardness profile over the build direction with high values (approximately 120 HV). The improved mechanical properties were due to the redistribution of the Si in form of a micrometric network in the Al-matrix along the deposit. The process was found to be a promising option for producing freestanding components, as well as adding features to existing parts with tailored properties, especially for lightweight applications.