Precipitation of homogeneous nanoscale HfRe2 in NiAl by strain-induced precipitation

Abstract

The precipitation of homogeneous nanoscale HfRe2 in NiAl grains was achieved by strain-induced precipitation at 1000 °C with a strain rate of 0.001 s−1. HfRe2 could not be precipitated under separate heating at 1000 °C, as the deformation increased, HfRe2 began to precipitate and gradually increased in size due to Ostwald ripening. The increase in hardness confirmed the occurrence of precipitation processes. A detailed discussion of the phase composition of the precipitates and their orientation relationship with the matrix was performed. The lattice mismatch at the NiAl111//HfRe227¯55.36⊥HfRe227¯53 interface was calculated to be only 3.90% based on the Bramfitt two-dimensional lattice mismatch theory, which demonstrated that HfRe2 could precipitate with NiAl as a heterogeneous nucleus.