An interdiffusion study of a NiAl alloy using single-phase diffusion couples

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 31; no. 6; pp. 1519 - 1524
• Main Authors: SUNGTAE KIM, CHANG, Y. A
• Format: Journal Article
• Language: English
• Published: New York, NY Springer 01.06.2000
• Subjects: Applied sciences; Chemical interdiffusion; diffusion barriers; Condensed matter: structure, mechanical and thermal properties; Diffusion in solids; Exact sciences and technology; Metals. Metallurgy; Physics; Transport properties of condensed matter (nonelectronic); Nickel base alloys; Temperature dependence; Point defects; Intermetallic compounds; Ordered alloy; Interdiffusion; Experimental study; Diffusion pair; Binary alloys; Aluminium alloys; Transport processes; Diffusion coefficient; Diffusion; Transition element alloys; Concentration distribution
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-000-0162-7

The intermetallic compound NiAl is highly ordered at stoichiometry, even at high temperatures. Various data suggest that the interdiffusion coefficient should exhibit a minimum at this composition, yet the literature data show that the minimum interdiffusion coefficient occurred between 48 and 49 at. pct Al. Accordingly, we have carried out diffusion-couple measurements employing single-phase NiAl wafers over the temperature interval from 700 C to 1000 C. The measured concentration profiles were analyzed in terms of the lattice mole fraction, yielding interdiffusion coefficients as a function of composition and temperature. For all the temperatures studied, the interdiffusion coefficients were found to exhibit a minimum at the stoichiometric composition, with a corresponding maximum in the activation energies obtained from the temperature dependence of the interdiffusion coefficients. (Author)