Coefficients of thermal expansion of (Ni 0·5 Al 0·5 ) (1–x) Hf x alloys (x =0...0·2)

P. Masset (1) , Damien Texier (1) , M. Schütze (1)

1 Karl Winnacker Institute

The coefficients of thermal expansion (CTEs) of Ni–Al–Hf alloys have been investigated due to their potential as corrosion resistant coatings in aggressive environments at high temperature. The CTEs of (Ni0·5Al0·5)(1–x)Hfx alloys (x=0...0·2) were measured between 473 and 1073 K (200–800°C) and range between 8 and 15×10–6 K–1 depending on temperature and alloy composition. The temperature dependence of the CTE was found to be properly described by a simple expression: (19·982–0·24016X Hf)[0·15182+1·8287×10–3(T/K)–2·12378×10–6(T/K)2+8·87011×10–10(T/K)3]. It was shown that the CTE of (Ni0·5Al0·5)(1–x)Hfx alloys varies linearly with the amount of Hf in the alloy which allows the control of the CTE. Within the (Ni0·5Al0·5)(1–x)Hfx alloy composition range (x=0...0·2) it covers the CTE range of most of the austenitic and ferritic steels and the CTE of the coatings can be adjusted to those of the substrate to be protected without inducing additional strains at the coatings/substrate interface.

Mots clés: AL–NI–HF; CTE; NIAL ALLOYS; HIGH TEMPERATURE; COEFFICIENTS OF THERMAL EXPANSION; CTE; NiAl alloys; Al–Ni–Hf; high temperature

Domaines: Matériaux

P. Masset, Damien Texier, M. Schütze. Coefficients of thermal expansion of (Ni 0·5 Al 0·5 ) (1–x) Hf x alloys (x =0...0·2). Materials Science and Technology, 2009, 25 (7), pp.874-879. ⟨10.1179/174328408X372083⟩. ⟨hal-01644852⟩