Engineers from the University of Ottawa, Ontario, Canada, have designed a hybrid Additive Manufacturing technology that can help to prevent delamination of soft and ductile materials from hard substrates, reports ASM International.
According to the engineers, delamination is a challenge when using the cold spray process, and additional heat treatment processes have typically been used to address this problem. Unfortunately, to achieve significant improvements, long and extensive heat treatments are required.
As a potential solution to this issue, the engineers developed a tunable hybrid Additive Manufacturing process by coupling induction heating and low-pressure cold spray.
Pure aluminium was used as the soft feedstock powder, while Ti-6Al-4V was used for the hard substrate. Substrates were preheated at temperatures of 200°C, 400°C, and 600°C to accelerate the in-situ sintering process. Deposition efficiency, micro-hardness, adhesion strength, and tensile strength were evaluated to characterise the in-situ sintering effect.
The engineers observed that deposition efficiency was doubled with the hybrid process, compared to the traditional low-pressure cold spray process. Additionally, the resulting adhesion strength was increased by a factor of 70, while the coating micro-hardness was reduced by 20%.
Finally, the tensile strength specimens produced by the hybrid process reached a 2% total elongation, compared to 0.8% for the traditional process. The engineers believe that these results open up the possibility of using this hybrid technique as an Additive Manufacturing process for coatings and bulk parts production.