2008•Journal of Material Science and TechnologyRequires access
Effect of heat treatment on the microstructure of multiphase NiAl-based alloy
Yi Xie, Lanzhang Zhou, Guo Jianting, Hengqiang Ye
Open publisher page 3 citations
Abstract
The alloy Ni-Al26.6-Cr13.4-Co8.1-Ti4.3-W1.3-Mo0.9 (at. pct) was fabricated from superalloy K44 and Al element using vacuum induction and casting technique. Investigations to this alloy reveal that a new phase Cr3Ni2 possessing low melting point and poor ductility is formed, which is distributed as a network along NiAl matrix grain boundaries. Subsequent different solution and aging treatments are carried out and lead to microstructural changes to various extents. Rapid cooling after solution at 1250 degrees C for 20 h gives rise to macrocracks in the specimen while slow cooling after the same treatment results in the formation of spheric alpha-Cr solid solution and needle-like Ni3Al phase, which are embedded in NiAl matrix. It is comfirmed that aging treatments initiate lath-shaped Ni3Al phase and pearl-shaped alpha-Cr phase to precipitate from the NiAl matrix, which own orientation relationships with these precipitates.