Correlation Between Cooling Rate and γ' Precipitate Size in Rene 95 Alloy Fabricated Through a Powder Metallurgy Process

초록

We investigated the correlation between the cooling rate and the cooling gamma ' (gamma '(c)) precipitate size in a Rene 95 alloy. The alloy powders were prepared through an electrode induction gas atomization, and the powders were consolidated by hot isostatic pressing. The solution heat treatment was performed using a gas-quenching furnace, which can control the cooling rate via the gas pressure. The samples were annealed at a sub-solvus temperature of 1135 degrees C, and argon was used as the quenching gas. Experiments were carried out under four conditions with quenching gas pressures of 1, 2, 3, and 9 bar. At these pressures, the cooling rate increased to 114.5 degrees C/min, 157.1 degrees C/min, 201.1 degrees C/min, and 282.9 degrees C/min, respectively. The average size of the gamma '(c) at the cooling rate of 114.5 degrees C/min was 133 nm, and it decreased to 88 nm at 282.9 degrees C/min. The power law relation was used to derive the equation for predicting the gamma '(c) size concerning the cooling rate, while the data obtained from this study and the results from a previous study were used to fit the power law equation. From the analysis, parameters of A and n were determined to 179.4 and 0.493, respectively.

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