Effect of heat treatment on the gas-atomized nickel‑aluminum bronze feedstock powders for cold spray

Abstract

Due to the high strength of the nickel‑aluminum bronze (NAB), the cold spray deposition efficiency of the NAB powders was less than satisfactory. To improve the deformation behavior of powder, different heat treatment strategies were adopted for gas atomized NAB powders and then the heat-treated powders were deposited on NAB substrates using a high-pressure cold spray system. For various powders and their corresponding deposits, a series of related characterizations were performed. The results indicate that the microstructure of the gas-atomized powder was mainly composed of martensitic β′ and bainite α with high hardness, resulting in low deposition efficiency and poor bonding between particles and particles in the prepared deposits. An effective technique of heat treatment can eliminate the non-equilibrium structure in the gas atomized powder, reduce the hardness of the powder, and significantly improve the deposition efficiency and enhance particle interface bonding.