Influence of solidification conditions on the castability of nickel-base superalloy IN792

Zhou, Yizhou; Volek, Andreas; Singer, Robert F.

doi:10.1007/s11661-005-0181-5

Cited by 40 publications

(29 citation statements)

References 17 publications

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“…In another investigation, 13 we found that solidification rate is able to affect the geometry and distribution of remaining liquid, although the volume fraction of the remaining liquid is independent of the solidification rate. The remaining liquid becomes more finely dispersed and increasingly discontinuous at a higher solidification rate because of the refinement of dendrites and columnar grains.…”

Section: Introductionmentioning

confidence: 76%

“…Therefore, dendrite arm spacing and columnar grain size were reduced simultaneously in the previous work 13 when the solidification rate was increased. As such, the effects of the dendrite arm spacing and columnar grain size on castability could not be studied separately.…”

Section: Introductionmentioning

confidence: 85%

“…In our previous work, 13 the nucleation at the start of DS process was controlled by the casting parameters (i.e., the temperature of melt and chill plate), not by a BC seeding procedure, as in the present article. Therefore, dendrite arm spacing and columnar grain size were reduced simultaneously in the previous work 13 when the solidification rate was increased.…”

Section: Introductionmentioning

confidence: 91%

“…The same result was found in IN792 in our previous work. 13 The GBs in CM247 are composed of continuous films , i.e., dendrites are assumed to be square shaped. 1 increases with increasing distance from the chill end because of change in the thermal gradient and 1 of CMSX-4 is smaller at a higher solidification rate.…”

Section: B Microstructure Characterizationmentioning

confidence: 99%

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Effect of grain boundary characteristics on hot tearing in directional solidification of superalloys

2006

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The effect of grain boundary (GB) misorientation on hot tearing susceptibility of directionally solidified (DS) nickel-based superalloys was explored. We found that the castability of second generation nickel-based superalloy CMSX-4 is inferior to DS superalloy IN792, an alloy well known for bad castability. The castability of CMSX-4 is somewhat improved at a higher solidification rate. The hot tearing tendency increases with increasing GB misorientation angle. As feeding tendency becomes greater with increasing misorientation, this points to the importance of GB cohesion for solidification cracking in the alloy. Microstructure investigation reveals that hot tearing is associated with formation of continuous gamma and gamma prime eutectic films at the GB in CMSX-4. We assume that the gamma and gamma prime eutectic, which reflects the remaining liquid at the end of solidification, prevents the impinging dendrite arms from touching and in this way decreases cohesion.

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Section: Introductionmentioning

confidence: 76%

Section: Introductionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 91%

Section: B Microstructure Characterizationmentioning

confidence: 99%

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Effect of grain boundary characteristics on hot tearing in directional solidification of superalloys

2006

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“…Moreover in another study Zhang and Singer (2004a,b) obtained a crack free specimen with grain boundary misorientation angle less than 12 • . Zhou et al (2005) investigated the grain boundary characteristics and proved that the presence of an interdendritic eutectic phase supresses hot tearing. Zhou and Volek (2006) explored the effect of grain boundary (GB) fraction and showed higher GB fraction has a positive effect on lowering the hot tear tendency.…”

Section: Introductionmentioning

confidence: 99%

Hot tearing in polycrystalline Ni-based IN738LC superalloy: Influence of Zr content

Heydari

Fard

Bakhshi

et al. 2014

Journal of Materials Processing Technology

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a b s t r a c tZirconium is always present in Ni base superalloys as it enhances their creep properties. In the present study, the influence of very small Zr additions, 100-400 ppm, i.e. 0.01-0.04 wt.%, on hot tearing of IN738LC superalloy is experimentally investigated using dedicated turbine blade castings. Although the Zr content remains very small, it has a strong effect on hot tearing tendency. Microstructure of hot tear in as-cast samples reveal that grain size and secondary dendrite arm spacing have no significant effect on hot tearing. On the other hand eutectic phase volume fraction and its dispersion or spreading along grain boundaries drastically affect the hot tearing propensity and strongly increase with increasing amounts of Zr. Hence grain coalescence becomes impossible at grain boundaries covered with eutectic phase films. With increasing Zr content, gain coalescence between two distinct grains with no interdendritic phase requires more undercooling. Coalescence is retarded and occurs deeper in the mush zone, i.e. at lower temperatures resulting in a higher sensitivity to hot tearing. Finally, it is shown that a reduction of Zr content to 0.02 wt.% is required to fully suppress hot tearing in polycrystalline IN738LC blades.

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Anisotropic Growth of the Primary Dendrite Arms in a Single‐Crystal Thin‐Walled Nickel‐Based Superalloy

et al. 2022

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The influence of the withdrawal rate and wall thickness on the primary and secondary dendrite arm spacings of single‐crystal specimens manufactured by the Bridgman process is investigated. Thin‐walled specimens with wall thicknesses of 0.4, 0.8, 1, and 2 mm are compared with conventional cast single‐crystal cylindrical specimens with a diameter of 15 mm of the nickel‐based superalloy MAR M247LC. It is found that the average primary dendrite arm spacing decreases slightly with decreasing wall thickness, whereas the secondary dendrite arm spacing is relatively independent of the cast wall thickness. The slight decrease in primary dendrite arm spacing relates to an ≈ 0.2 mm wide boundary zone next to the ceramic mold/cast metal interface that is not only present in the thin‐walled specimens, but also within cylindrical single‐crystal specimens. Within this boundary zone, the primary dendrite arm spacing is anisotropic. While the spacing of two dendritic cores sitting aside each other (y‐direction) remains at the bulk value, the spacing of two dendritic cores sitting in line with the interface normal (x‐direction) is significantly reduced.

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Influence of solidification conditions on the castability of nickel-base superalloy IN792

Cited by 40 publications

References 17 publications

Effect of grain boundary characteristics on hot tearing in directional solidification of superalloys

Effect of grain boundary characteristics on hot tearing in directional solidification of superalloys

Hot tearing in polycrystalline Ni-based IN738LC superalloy: Influence of Zr content

Anisotropic Growth of the Primary Dendrite Arms in a Single‐Crystal Thin‐Walled Nickel‐Based Superalloy

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