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The alloy Ni-AI26.6-Cr13.4-CoS.1-Ti4.3-W1.3-Mo0.9(at,pct) was fabricated from superalloy K44 and AI element using vacuum induction and casting technique.Investigations to this alloy reveal that a new phase Cr_3Ni_2 possessing low melting point and poor ductility is formed,which is distributed as a network along NiAI 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℃for 20 h gives rise to macrocracks in the specimen while slow cooling after the same treatment results in the formation of sphericα-Cr solid solution and needle-like Ni_3Al phase,which are embedded in NiAI matrix.It is comfirmed that aging treatments initiate lath-shaped Ni_3Al phase and pearl-shapedα-Cr phase to precipitate from the NiAI matrix,which own orientation relationships with these precipitates.
The alloy Ni-AI26.6-Cr13.4-CoS.1-Ti4.3-W1.3-Mo0.9 (at, pct) was fabricated from superalloy K44 and AI element using vacuum induction and casting technique. Investigations to this alloy reveal that a new phase Cr_3Ni_2 possessing low melting point and poor ductility is formed, which is distributed as a network along NiAI 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 ° C for 20 h gives rise to macrocracks in the specimen while slow cooling after the same treatment results in the formation of spheric α-Cr solid solution and needle-like Ni_3Al phase, which are embedded in NiAI matrix. It is comfirmed that aging which lath-shaped Ni_3Alphase and pearl-shapedα-Cr phase to precipitate from the NiAI matrix, which has orientation relationships with these precipitates.