Precipitate growth activation energy requirements in the duplex size γ′ distribution in the superalloy IN738LC

Roy, Indranil; Balikci, Ercan; Ibekwe, Samuel; Raman, A.

doi:10.1007/s10853-005-3154-6

Cited by 37 publications

(18 citation statements)

References 3 publications

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“…The 24-hour treatments give an intermediate value of 246 kJ/mol. This finding, in line with that reported by Roy et al, [37] shows that the coarsening becomes easier with longer aging time. This and the previous observations documented in the literature [36] suggest that activation energy is not constant but varies through different regimes of precipitate evolution.…”

Section: Kineticssupporting

confidence: 93%

Multimodal Precipitation in the Superalloy IN738LC

Balikci

Erdeniz

2010

Metall Mater Trans A

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ERCAN BALIKCI and DINC ERDENIZIN738LC is a polycrystalline, nickel-base superalloy, which is used in aggressive environments at high temperatures. The required strength is provided by precipitate strengthening. Both unimodal and multimodal precipitate distributions are observed in IN738LC. After reaching a critical size, a unimodal precipitate microstructure transforms to a bimodal one. This transformation is controlled by the precipitate-matrix interface, which is under compression in IN738LC. As the unimodal precipitates grow, the strained interface, due to differential lattice parameter of the matrix and the precipitate phase, stops solute diffusion into the growing precipitates. Hence, the solute atoms, entrapped in the matrix, saturate the matrix and form new, fine precipitates. Dissolution of some large precipitates also supplies solute to supersaturate the matrix. On the other hand, a multimodal precipitate distribution tends to become unimodal at low aging temperatures and bimodal at high aging temperatures. Interestingly, the activation energy is calculated for the coarsening of large precipitates in multimodal distribution and is found to vary with aging time.

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Section: Kineticssupporting

confidence: 93%

Multimodal Precipitation in the Superalloy IN738LC

Balikci

Erdeniz

2010

Metall Mater Trans A

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“…8(a), merging of remnant precipitates with neighboring cooling ones has occurred. Such an agglomeration of coarse and fine precipitates has been reported by some investigators and presented as a precipitate growth mechanism [30][31][32]. Contrarily, the lack of cooling precipitates in the damaged microstructure after cycle A (Fig.…”

Section: Solution Treatment and Subsequent Coolingsupporting

confidence: 70%

Microstructural evolution in damaged IN738LC alloy during various steps of rejuvenation heat treatments

Hosseini

Nategh

Ekrami

2012

Journal of Alloys and Compounds

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“…where, Q e molar diffusion activation energy, (kJ mol À1 ) R e universal gas constant, (J mol À1 K À1 ), d 1 and d 2 are the average particle sizes (nm) at respective temperatures of T1 (K) and T2 (K), The above equation is obtained by substituting the precipitate size data for respective tempering temperatures and time in Equations (2) and (3), where the value of d 0 is assumed as very small and negligible [17,18].…”

Section: Microstructurementioning

confidence: 99%