Hybrid additive manufacturing technology: Induction Heating Cold Spray

Delamination of soft and ductile materials from hard substrates is a challenge when using the cold spray process. Typically, additional heat treatment processes have been used to address this problematic. Unfortunately, to produce significant improvements, long and extensive heat treatments are required. As a potential solution to this issue, a tunable hybrid additive manufacturing process was developed by coupling induction heating and low pressure cold spray processes. Pure aluminum was used as the soft feedstock powder while Ti-6Al-4V was used for the hard substrate. Substrate preheating temperatures of 200ºC, 400ºC, and 600ºC were used to accelerate the in-situ sintering process. Deposition efficiency, micro-hardness, adhesion strength and tensile strength were evaluated to characterize the in-situ sintering effect. It was observed that the deposition efficiency was doubled with the hybrid process compared to the traditional low pressure cold spray process. Additionally, the resulting adhesion strength was increased 70 times while the coatings micro-hardness was by reduced 20%. Finally, the tensile strength specimens produced by the hybrid process reached a 2% total elongation compared to 0.8% for the traditional process. These results open up the possibility of using this hybrid technique as an additive manufacturing process for coatings and bulk parts production.