Matrix Transformation in Boron Containing High-Temperature Co–Re–Cr Alloys

Strunz, Pavel; Mukherji, D.; Béran, P.; Gilles, Ralph; Karge, Lukas; Hofmann, M.; Hoelzel, Markus; Rösler, Joachim; Farkas, Gergely

doi:10.1007/s12540-018-0121-8

Cited by 8 publications

(16 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…ppm B, i.e., 0.36 and 0.72 at %) exhibited splitting of the ε matrix phase peaks at HT [6]. After the in-situ HT cycle, it was observed that these two samples (500 and 1000 wt.…”

Section: In-situ Thermal Cycle During Neutron Diffraction Measurementmentioning

confidence: 95%

“…The microstructure of the initial state of the samples from the various alloys (ST condition) was presented in the earlier paper [6]. The microstructures after the in-situ neutron diffraction measurement at HT are presented here.…”

Section: Sem and Edsmentioning

confidence: 98%

“…In Figure 3 (taken from [6]), the intensity maps are reported from the diffractograms taken during the in-situ thermal cycles for three of the studied samples (150, 500 and 1000 wt. ppm of boron).…”

Section: Neutron Diffraction Measurements At Htmentioning

confidence: 99%

“…The color-map intensity levels (the color range is shown on the right) were selected in such a way that the weaker reflections are also clearly visible. The graphs are reproduced from [6], with permission from Springer Nature, 2018.…”

Section: Neutron Diffraction Measurements At Htmentioning

confidence: 99%

“…Neutron diffraction (ND) was already successfully used for in-situ structural studies of these alloys at high temperatures [3][4][5]. The structure and phase transformation of boron-containing Co-Re-Cr alloys at high temperatures (HT) were investigated in the neutron-scattering experiment described in [6]. It was shown that boron significantly changes the allotropic transformation temperature of the Co solid solution matrix, i.e., transformation temperature from low-temperature hexagonal close-packed phase (hcp, alternatively denoted ε) to high-temperature cubic face centered structure (fcc or γ).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Additional Phases at High Boron Content in High-Temperature Co–Re–Cr Alloys

Béran

Mukherji

Strunz

et al. 2018

Metals

Self Cite

View full text Add to dashboard Cite

Boron largely increases the ductility of polycrystalline high-temperature Co-Re-Cr alloys. Therefore, the effect of boron addition on the alloy structural characteristics is of large importance for the stability of the alloy at operational temperatures. Along with the Co-solid solution matrix phase transformation from hcp to fcc structure, additional structural effects were observed in situ at very high temperatures (up to 1500 • C) using neutron diffraction (ND) in boron-containing Co-17Re-23Cr alloys. Increasing boron content up to 1000 wt. ppm lowers the temperature at which sublimation of Co and Cr from the matrix occurs. As a result, the composition of the matrix in the surface region is changed leading to the formation of a second and a third matrix hcp phases at high temperatures. The consideration on the lattice parameter dependence on composition was used to identify the new phases appearing at high temperatures. Energy-dispersive spectroscopy and ND results were used to estimate the amount of Co and Cr which sublimated from the surface region of the high-boron sample. In the sense of alloy development, the sublimation of Co and Cr is not critical as the temperature range where it is observed (≥1430 • C) is significantly above the foreseen operation temperature of the alloys (1200 • C).

show abstract

“…ppm B, i.e., 0.36 and 0.72 at %) exhibited splitting of the ε matrix phase peaks at HT [6]. After the in-situ HT cycle, it was observed that these two samples (500 and 1000 wt.…”

Section: In-situ Thermal Cycle During Neutron Diffraction Measurementmentioning

confidence: 95%

Section: Sem and Edsmentioning

confidence: 98%

Section: Neutron Diffraction Measurements At Htmentioning

confidence: 99%

Section: Neutron Diffraction Measurements At Htmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Additional Phases at High Boron Content in High-Temperature Co–Re–Cr Alloys

Béran

Mukherji

Strunz

et al. 2018

Metals

Self Cite

View full text Add to dashboard Cite

show abstract

TaC Precipitation Kinetics During Cooling of Co−Re‐Based Alloys

et al. 2021

Self Cite

View full text Add to dashboard Cite

CobaltÀrhenium (CoÀRe) alloys are developed for high-temperature applications at %1200 C and are strengthened by dispersion of nanosized tantalum carbide (TaC) precipitates. Herein, the precipitation behavior during cooling from supersolution depending on the cooling rate and the addition of chromium is presented. The phase composition (matrix phases and TaC) is analyzed from the wide-angle neutron diffraction patterns measured in situ during temperature cycling. The precipitation of nanosized TaC particles is measured by in situ and ex situ neutron and X-ray small-angle scattering. The in situ measurements are used to extract the temperature-dependent volume fraction of the precipitates; the final size distribution after cooling is extracted from the ex situ measurements. A KampmannÀWagner's numerical (KWN) model is adapted to isochronal cooling processes. The in situ measurements give the unique possibility to calibrate the model parameters, whereas the ex situ measurements are used to assess the model predictions.

show abstract