Effects of C and Hf concentration on phase relations and microstructure of a wrought powder-metallurgy superalloy
Tóm tắt
NASA IIB-11, a candidate alloy for advanced temperature turbine engine disks, and four modifications with varying C and Hf concentrations were produced from prealloyed powders. Several notable effects of C and Hf concentration in the alloys were observed. Both the amount of the γ′ phase and its solvus temperature increased with decreasing C, but only the γ′ solvus was affected by Hf, increasing with increasing Hf. Hf also promoted a cellular γ′ precipitation. Hf was, however, about equally distributed between γ′ and γ. Hf and C both affected the carbides formed. Increasing both promoted formation of an MC relative to that of an M6C.
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