{"title":"Microstructure control and DRX characteristics of Ni–Co–W superalloys affected by changing deformation direction on [001] columnar grain","authors":"","doi":"10.1016/j.jmrt.2024.09.110","DOIUrl":null,"url":null,"abstract":"<div><p>Controlling the evolution process of columnar grains is benefits to achieve microstructure regulation during subsequent hot processing in superalloys. In present research, it takes a Ni–Co–W superalloy as an example, aims to clarify the underlying connections between the compression direction and dynamic recrystallization (DRX) behaviors in microstructure evolution. The compression direction (CD) was parallel or perpendicular to [001] columnar has been defined as CD∥[001] and CD⊥[001], respectively. The columnar evolution and DRX characteristics under two sets of experimental during hot deformation were identified deeply. The results show that complete DRX is more easily to occur when CD⊥[001], but fine DRX grains are tendency to form when CD∥[001]. DRX nucleation within CD∥[001] and CD⊥[001] deformed microstructure under dislocation energy was discussed deeply. The critical size of nucleation is decreased while the nucleation density is increased in CD∥[001] with high dislocation density, which benefits to form numerous fine DRX grains along the original columnar boundaries. In addition, according to Taylor factors (TFs) criterion, TFs difference will always existed in CD∥[001], which promotes the necklace structure gradually replaced columnar structure and some of them developed into fine DRX bands. With increasing of trues strain, TFs difference gradually decreased in CD⊥[001], DRX nucleation was inhibited, thus the existed DRX grains further grow and finally coarse DRX grains were obtained. The findings clarified the flow behaviors and DRX characteristics of [001] columnar in two directions, and then proposed a microstructure control mechanism of superalloys with [001] columnar based on deformation vector and evolution decomposition.</p></div>","PeriodicalId":54332,"journal":{"name":"Journal of Materials Research and Technology-Jmr&t","volume":null,"pages":null},"PeriodicalIF":6.2000,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2238785424021148/pdfft?md5=8b37eb17d986f6b63af4a9e1a0c92190&pid=1-s2.0-S2238785424021148-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Materials Research and Technology-Jmr&t","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2238785424021148","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Controlling the evolution process of columnar grains is benefits to achieve microstructure regulation during subsequent hot processing in superalloys. In present research, it takes a Ni–Co–W superalloy as an example, aims to clarify the underlying connections between the compression direction and dynamic recrystallization (DRX) behaviors in microstructure evolution. The compression direction (CD) was parallel or perpendicular to [001] columnar has been defined as CD∥[001] and CD⊥[001], respectively. The columnar evolution and DRX characteristics under two sets of experimental during hot deformation were identified deeply. The results show that complete DRX is more easily to occur when CD⊥[001], but fine DRX grains are tendency to form when CD∥[001]. DRX nucleation within CD∥[001] and CD⊥[001] deformed microstructure under dislocation energy was discussed deeply. The critical size of nucleation is decreased while the nucleation density is increased in CD∥[001] with high dislocation density, which benefits to form numerous fine DRX grains along the original columnar boundaries. In addition, according to Taylor factors (TFs) criterion, TFs difference will always existed in CD∥[001], which promotes the necklace structure gradually replaced columnar structure and some of them developed into fine DRX bands. With increasing of trues strain, TFs difference gradually decreased in CD⊥[001], DRX nucleation was inhibited, thus the existed DRX grains further grow and finally coarse DRX grains were obtained. The findings clarified the flow behaviors and DRX characteristics of [001] columnar in two directions, and then proposed a microstructure control mechanism of superalloys with [001] columnar based on deformation vector and evolution decomposition.
期刊介绍:
The Journal of Materials Research and Technology is a publication of ABM - Brazilian Metallurgical, Materials and Mining Association - and publishes four issues per year also with a free version online (www.jmrt.com.br). The journal provides an international medium for the publication of theoretical and experimental studies related to Metallurgy, Materials and Minerals research and technology. Appropriate submissions to the Journal of Materials Research and Technology should include scientific and/or engineering factors which affect processes and products in the Metallurgy, Materials and Mining areas.