High temperature deformation behaviour and dislocation substructure of impacted Inconel 625 alloy
| Autor: | Chien-WeiHuang, 黃建瑋 |
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| Rok vydání: | 2017 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 105 Dynamic impact response and microstructural characteristics of Inconel 625 alloy are investigated under strain rates ranging from 3700s−1 to 6400s−1 and different temperatures of 25ºC, 300ºC and 750ºC, respectively, using a compressive split-Hopkinson pressure bar. The results indicate that mechanical properties of Inconel 625 alloy are sensitive to temperature and strain rate. At a constant temperature, flow stress, work hardening rate, strain rate sensitivity and temperature sensitivity all increase, but the thermal activation volume and activation energy decrease with the increasing strain rate. However, at a constant strain rate, flow stress, work hardening rate, strain rate sensitivity, and temperature sensitivity decrease but the thermal activation volume and activation energy increase with increasing temperature. A Zerilli-Armstrong constitutive equation is used to describe the deformation behavior of Inconel 625 alloy under tested conditions. Optical Microscope(OM) observations reveal that there are MC and M23C6 carbides participated in Inconel 625 alloy. The intergranular crack and failure are observed under 750ºC condition. Furthermore, Transmission Electron Microscopy(TEM) observations show that the dislocation density increases with increasing strain rate, but decreases with increasing temperature. The relationship between the dislocation density and the stress can be expressed using the Bailey-Hirsch equation. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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