| Autor: |
Wei Jiang, Pingwei Xu, Yayun Li, Haidou Wang, Zhihai Cai, Jing Li, Yilong Liang, Yu Liang |
| Jazyk: |
angličtina |
| Rok vydání: |
2023 |
| Předmět: |
|
| Zdroj: |
Journal of Materials Research and Technology, Vol 23, Iss , Pp 2031-2042 (2023) |
| Druh dokumentu: |
article |
| ISSN: |
2238-7854 |
| DOI: |
10.1016/j.jmrt.2023.01.121 |
| Popis: |
The effect of a gradient structure (GS) with present precipitates on the tensile properties of Inconel 718 (IN718) alloy at elevated temperatures was studied. A high-density δ-Ni3Nb phase and fine recrystallized γ grains were obtained in the surface gradient layer using an ultrasonic surface-rolling process (USRP) and subsequent heat treatment. The amount of the δ phase in the gradient layer decreased with the layer depth, while the size of the recrystallized γ grains exhibited an opposite trend. Remarkably, the GS did not show a microhardness gradient at room temperature but exhibited excellent strength and plasticity during high-temperature tensile tests. Compared with a uniform sample, the yield strength (YS) and ultimate tensile strength (UTS) of the specimen with a GS increased by 55 and 105 MPa, respectively, and the plasticity increased by 25% in the tensile tests at 650 °C. The δ phase pinned the RANS-scale grain hierarchy in the gradient layer and improved the thermal stability at 650 ℃. This GS promoted the accumulation of high-density geometrically necessary dislocations (GNDs) in the gradient layer during plastic deformation, resulting in additional back-stress strengthening. Therefore, forming a gradient structure with precipitates provides a new approach toward a good combination of strength and ductility at elevated temperatures. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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