Cold Spray Deposition of HY80 High Strength Steel

In this presentation, we will share successful results on the cold spray and laser-assisted cold spray (LACS) deposition of HY80 steel. HY80 is a high strength, Ni-Cr-Mo, ferritic-martensitic steel used in a variety of structural and ship building applications. We have successfully used both high pressure cold spray and LACS to deposit this material onto HY80 substrates using helium as the spray gas. All depositions were produced using gas-atomized HY80 powder and a VRC Metal Systems high pressure cold spray instrument, equipped with a custom Laserline LDM-4000 infrared laser system and optical pyrometer. The deposition efficiency of HY80 was quite high, with a mass deposition efficiency of 70-80 percent. Unexpectedly, nozzle fouling was prevalent for this alloy using a tungsten carbide nozzle, but this problem was remedied by water cooling of the spray nozzle. Using the in situ laser heating to produce a surface temperature of 500˚C (<A₁) did not affect the deposition efficiency, but it did reduce the porosity to less than 0.5%. We are also exploring LACS at higher applied surface temperatures for this steel. We will present the connections between spray parameters and deposition microstructures for this steel using a variety of electron microscopy techniques.