English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Predicting the mechanical failure of parts in service requires understandingtheir deformation behavior, and associated dynamic microstructural evolution upto the near-atomic scale. Solutes are known to interact with defects generatedby plastic deformation, thereby affecting their displacement throughout themicrostructure and hence the material mechanical response to solicitation. Thiseffect is studied here in a polycrystalline Ni-based superalloy with twodifferent Nb contents that lead to a significant change in their creeplifetime. Creep testing at 750C and 600 MPa shows that the high-Nb alloyperforms better in terms of creep strain rate. Considering the similar initialmicrostructures, the difference in mechanical behavior is attributed to a phasetransformation that occurs along planar faults, controlled by the differenttypes of stacking faults and alloy composition. Electron channeling contrastimaging reveals the presence of stacking faults in both alloys. Microtwinningis observed only in the low-Nb alloy, rationalizing in part the higher creepstrain rate. In the high-Nb alloy, atom probe tomography evidences twodifferent types of stacking faults based on their partitioning behavior.Superlattice intrinsic stacking faults (SISF) were found enriched in Nb, Co, Crand Mo while only Nb and Co was segregated at superlattice extrinsic stackingfaults. Based on their composition, a local phase transformation occurringalong the faults is suggested, resulting in slower creep strain rate in thehigh-Nb alloy. In comparison, mainly SISF enriched in Co, Cr, Nb and Mo werefound in the low-Nb alloy. Following the results presented here, and thoseavailable in the literature, an atomic-scale driven alloy design approach thatcontrols and promotes local phase transformation along planar faults at 750C isproposed, aiming to design superalloys with enhanced creep resistance.

Enhanced creep performance in a polycrystalline superalloy driven by atomic-scale phase transformation along planar faults