Partners

Abstract:
In this paper, the effect of hafnium, titanium, and molybdenum addition on the microstructure and properties of the aluminide layers deposited by using a chemical vapor deposition process on IN 713C nickel superalloy substrate was discussed. A multi-component aluminide diffusion layer containing Ni–Al, Al–Ti–Ni, and hafnium-rich phases was successfully formed by aluminizing IN 713C nickel superalloy. Subsequently performed corrosion resistance tests confirmed the beneficial effect of the aluminide layer deposited on IN 713C as compared to substrate material. Anticipating improved mechanical response of coated material, density functional theory calculations were performed. It was found that a single Hf/Ti/Mo atom prefers to be positioned within the Al sublattice in the NiAl, and Ni3Al phases. This justifies the presence of the experimentally observed Ni3Hf phase in the Hf-enriched IN 713C. The Hf modification effects on the NiAl, and Ni3Al were further discussed based on the changes of the elastic constants Cij, bulk modulus B, and shear modulus G. The presence of Hf in NiAl causes a decrease of phase’s C12 and C44 values, and increase in the C11 value. It was found that Hf modification of the Ni3Al causes a decrease in the Cij values and a slight decrease of phase’s B/G ratio, indicating a less ductile character of modified phase decohesion.

Keywords:
IN 713C, CVD, Aluminide layer, Corrosion resistance, SEM, Ab initio calculations