Young's moduli of cold and vacuum plasma sprayed metallic coatings

Monolithic metallic copper alloy and NiCrAlY coatings were fabricated by either the cold spray (CS) or the vacuum plasma spray (VPS) deposition processes. Dynamic elastic modulus property measurements were conducted on these monolithic coating specimens between 300 and 1273 K using the impulse excitation technique. The Young's moduli decreased almost linearly with increasing temperature at all temperatures except in the case of the CS Cu–23%Cr–5%Al and VPS NiCrAlY, where deviations from linearity were observed above a critical temperature. It was observed that the Young's moduli for VPS Cu–8%Cr were larger than the literature data compiled for Cu. The addition of 1%Al to Cu–8%Cr significantly increased its Young's modulus by 12–17% presumably due to a solid solution effect. Comparisons of the Young's moduli data between two different measurements on the same CS Cu–23%Cr–5%Al specimen revealed that the values measured in the first run were about 10% higher than those in the second run. It is suggested that this observation is due to annealing of the initial cold work microstructure resulting form the cold spray deposition process.