Investigation of the y´ Precipitates Dissolution in a Ni-Based Superalloy During Stress-Free Short-Term Annealing at High Homologous TemperaturesShow others and affiliations
2021 (English)In: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 52, no 11, p. 4767-4784Article in journal (Refereed) Published
Abstract [en]
The equiaxed Ni-based superalloy Rene 108 was subjected to short-term annealing at five temperatures between 900 degrees C and 1100 degrees C. The phase composition, phase lattice parameters, microstructure, stereological parameters, and chemical composition of y´ precipitates were investigated by thermodynamic simulations, X-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Analysis of the y and y´ lattice parameters using the Nelson-Riley extrapolation function showed that the misfit parameter for temperatures 900 degrees C to 1050 degrees C is positive (decreasing from 0.32 to 0.11 pct). At 1100 degrees C, the parameter becomes negative, delta = - 0.18 pct. During the short-term annealing, gamma ‘ precipitates dissolution occurred progressing more rapidly with increasing temperatures. The surface fraction of y´ precipitates decreased with increasing temperature from 0.52 to 0.34. The dissolution of gamma ‘ precipitates did not only proceed through uninterrupted thinning of each individual precipitate, but also included more complex mechanisms, including splitting. Based on transmission electron microscopy, it was shown that after y´ precipitates dissolution, the matrix close to the y/y interface is strongly enriched in Co and Cr and depleted in Al.
Place, publisher, year, edition, pages
SPRINGER , 2021. Vol. 52, no 11, p. 4767-4784
Keywords [en]
gamma, preciptitate, dissolution, ni-based superalloy, homologogues, temperatures. Rene 108
National Category
Manufacturing, Surface and Joining Technology Metallurgy and Metallic Materials Materials Chemistry
Research subject
Production Technology
Identifiers
URN: urn:nbn:se:hv:diva-17439DOI: 10.1007/s11661-021-06420-4ISI: 000692995500001Scopus ID: 2-s2.0-85114327029OAI: oai:DiVA.org:hv-17439DiVA, id: diva2:1603759
Note
This work was supported by the Polish National Science Centre (Preludium 13) under grant 2017/25/N/ST8/02368. The authors wish to express appreciation to prof. Wiktoria Ratuszek (AGH-UST) for supporting the XRD study.
2021-10-182021-10-182022-04-04