High-temperature strength of Ni-doped IrAl with the B2 type ordered crystal structure

Constant-velocity and constant-load compression tests have been conducted to examine the mechanical behavior of polycrystalline Ir(1-x)Ni(x)Al intermetallic compounds with x=0 to 1.0 at elevated temperatures. Ductility of Ir(1-x)Ni(x)Al is improved with increasing x, while the strength decreases with increasing x in the intermediate temperature range. The specific strength of Ir(1-x)Ni(x)Al is almost independent of x at temperatures higher than approximately 1473 K. Secondary creep of IrAl and Ir(0.2)Ni(0.8)Al (i.e. modified NiAl) exhibits class II and class I behavior, respectively. Creep strength of Ir(1-x)Ni(x)Al is about a magnitude of four higher than that of single-phase and multi-phase NiAl at a given applied stress. The Ir(1-x)Ni(x)Al intermetallic compound is superior to binary IrAl as a high-temperature structural material from the viewpoint of the specific strength, ductility and resistance to oxidation, especially at temperatures higher than 1473 K. Published by Elsevier Science Limited. All rights reserved.