Study of the Effects of Aging Treatment on Astroloy Processed via Hot Isostatic Pressing

Bassini, Emilio; Cattano, Giulio; Marchese, Giulio; Biamino, Sara; Ugues, Daniele; Lombardi, Mariangela; Vallillo, Gianfranco; Picqué, B.

doi:10.3390/ma12091517

Cited by 8 publications

(11 citation statements)

References 47 publications

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“…In the past, steel alloys were used as the main component of engines, but nowadays other alloys such as nickel base superalloys have gained prominence. Nickel superalloys are widely used due to their magnificent properties, even at extreme temperatures, which are provided by the high-volume fraction of gamma prime (γ ; Ni 3 (Al, Ti)) precipitates that is usually above the 50% of the alloy [1][2][3][4][5][6][7][8][9][10][11]. These alloys usually include other elements such as Cr, Co, Mo and W in order to reinforce the matrix.…”

Section: Introductionmentioning

confidence: 99%

“…These alloys usually include other elements such as Cr, Co, Mo and W in order to reinforce the matrix. However, the control of these alloying elements is crucial as they tend to form different carbides and strongly segregate in ingots, decreasing the materials' machinability [5,8,9,[12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…of the alloy [1][2][3][4][5][6][7][8][9][10][11]. These alloys usually include other elements such as Cr, Co, Mo and W in order to reinforce the matrix.…”

Section: Introductionmentioning

confidence: 99%

“…After solutioning, more precipitation treatments are usually applied in order to promote the precipitation of more and finer γ′. These HTs involve a competition between the formation of new γ′ and the coarsening of the previous one by an Ostwald-ripening process, usually the tendency is to diminish the number of precipitates with the goal of reducing the interfacial energy between γ and γ′ [9,11,[31][32][33].…”

Section: Introductionmentioning

confidence: 99%

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Thermal Mass Effect on the Solution Cooling Rate and on HIPped Astroloy Component Properties

et al. 2022

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Astroloy is a Ni-based superalloy with high-volume fraction of γ′, which gives high temperature properties but reduces its forgeability. Therefore, powder metallurgy manufacturing processes such as Near Net Shape HIPping are the most suitable manufacturing technology for Astroloy. However, NNSHIP has its own drawbacks, such as the formation of prior particle boundaries (PPBs), which usually tend to decrease material mechanical properties. The detrimental effect of PPBs can be reduced by optimizing the entire HIP processing route. Conventional HIP cycles have very low cooling rates, especially in big components from industry, and thus a series of post-heat treatments must be applied in order to achieve desirable microstructures and improve the mechanical properties. Standard heat treatments for Astroloy are long and tedious with several steps of solutioning, stabilization and precipitation. In this work, two main studies have been performed. First, the effect of the cooling rate after the solutioning treatment, which is driven by the materials’ thermal mass, on the Astroloy microstructure and mechanical properties was studied. Experimental analyses and simulation techniques have been used in the present work and it has been found that higher cooling rates after solutioning increase the density of tertiary γ′ precipitates by 85%, and their size decreases by 22%, which leads to an increase in hardness from 356 to 372 HB30. This hardness difference tends to reduce after subsequent standard heat treatment (HT) that homogenizes the microstructure. The second study shows the effect of different heat treatments on the microstructure and hardness of samples with two different thermal masses (can and cube). More than double the density of γ′ precipitates was found in small cubes in comparison with cans with a higher thermal mass. Therefore, the hardness in cubes is between 4 and 20 HB 30 higher than in large cans, depending on the applied HT.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…of the alloy [1][2][3][4][5][6][7][8][9][10][11]. These alloys usually include other elements such as Cr, Co, Mo and W in order to reinforce the matrix.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Thermal Mass Effect on the Solution Cooling Rate and on HIPped Astroloy Component Properties

et al. 2022

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“…The authors wish to make the following correction to the paper [1]. Due to a copyright issue in Figure 1, replace: These changes have no material impact on the discussion and conclusions of the paper.…”

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confidence: 99%