Microstructural Evolution along the NiCrMoV Steel Welded Joints Induced by Low-Cycle Fatigue Damage
The degradation of mechanical properties of materials is essentially related to microstructural changes under service loadings, while the inhomogeneous degradation behaviors along welded joints are not well understood. In the present work, microstructural evolution under low-cycle fatigue in base me...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-05-01
|
| Series: | Metals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-4701/11/5/811 |
| _version_ | 1797533896153235456 |
|---|---|
| author | Shuo Weng Yuhui Huang Mingliang Zhu Fuzhen Xuan |
| author_facet | Shuo Weng Yuhui Huang Mingliang Zhu Fuzhen Xuan |
| author_sort | Shuo Weng |
| collection | DOAJ |
| description | The degradation of mechanical properties of materials is essentially related to microstructural changes under service loadings, while the inhomogeneous degradation behaviors along welded joints are not well understood. In the present work, microstructural evolution under low-cycle fatigue in base metal (BM) and weld metal (WM) of NiCrMoV steel welded joints were investigated by miniature tensile tests and microstructural observations. Results showed that both the yield strength and ultimate tensile strength of the BM and WM decreased after low-cycle fatigue tests, which were attributed to the reduction of dislocation density and formation of low-energy structures. However, the microstructural evolution mechanisms in BM and WM under the same cyclic loadings were different, i.e., the decrease of dislocation density in BM was attributed to the dislocation pile-ups along the grain boundaries, dislocation tangles around the carbides at the lower strain amplitudes (±0.3% or ±0.5%). Additionally, when the strain amplitude was ±8%, the dislocation density was further decreased by the formation of subgrains in BM. For WM, the dislocation density decreased with the increase of strain amplitude, which was mainly caused by the dislocation pile-ups along the grain boundaries and the formation of subgrains. |
| first_indexed | 2024-03-10T11:22:11Z |
| format | Article |
| id | doaj.art-9624d3ad27c248eaab36fa050260e9a4 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-10T11:22:11Z |
| publishDate | 2021-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-9624d3ad27c248eaab36fa050260e9a42023-11-21T19:58:18ZengMDPI AGMetals2075-47012021-05-0111581110.3390/met11050811Microstructural Evolution along the NiCrMoV Steel Welded Joints Induced by Low-Cycle Fatigue DamageShuo Weng0Yuhui Huang1Mingliang Zhu2Fuzhen Xuan3School of Mechanical Engineering, University of Shanghai for Science and Technology, Shanghai 200093, ChinaSchool of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, ChinaSchool of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, ChinaSchool of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, ChinaThe degradation of mechanical properties of materials is essentially related to microstructural changes under service loadings, while the inhomogeneous degradation behaviors along welded joints are not well understood. In the present work, microstructural evolution under low-cycle fatigue in base metal (BM) and weld metal (WM) of NiCrMoV steel welded joints were investigated by miniature tensile tests and microstructural observations. Results showed that both the yield strength and ultimate tensile strength of the BM and WM decreased after low-cycle fatigue tests, which were attributed to the reduction of dislocation density and formation of low-energy structures. However, the microstructural evolution mechanisms in BM and WM under the same cyclic loadings were different, i.e., the decrease of dislocation density in BM was attributed to the dislocation pile-ups along the grain boundaries, dislocation tangles around the carbides at the lower strain amplitudes (±0.3% or ±0.5%). Additionally, when the strain amplitude was ±8%, the dislocation density was further decreased by the formation of subgrains in BM. For WM, the dislocation density decreased with the increase of strain amplitude, which was mainly caused by the dislocation pile-ups along the grain boundaries and the formation of subgrains.https://www.mdpi.com/2075-4701/11/5/811microstructurefatiguedislocationsstrengthtransmission electron microscopy (TEM) |
| spellingShingle | Shuo Weng Yuhui Huang Mingliang Zhu Fuzhen Xuan Microstructural Evolution along the NiCrMoV Steel Welded Joints Induced by Low-Cycle Fatigue Damage Metals microstructure fatigue dislocations strength transmission electron microscopy (TEM) |
| title | Microstructural Evolution along the NiCrMoV Steel Welded Joints Induced by Low-Cycle Fatigue Damage |
| title_full | Microstructural Evolution along the NiCrMoV Steel Welded Joints Induced by Low-Cycle Fatigue Damage |
| title_fullStr | Microstructural Evolution along the NiCrMoV Steel Welded Joints Induced by Low-Cycle Fatigue Damage |
| title_full_unstemmed | Microstructural Evolution along the NiCrMoV Steel Welded Joints Induced by Low-Cycle Fatigue Damage |
| title_short | Microstructural Evolution along the NiCrMoV Steel Welded Joints Induced by Low-Cycle Fatigue Damage |
| title_sort | microstructural evolution along the nicrmov steel welded joints induced by low cycle fatigue damage |
| topic | microstructure fatigue dislocations strength transmission electron microscopy (TEM) |
| url | https://www.mdpi.com/2075-4701/11/5/811 |
| work_keys_str_mv | AT shuoweng microstructuralevolutionalongthenicrmovsteelweldedjointsinducedbylowcyclefatiguedamage AT yuhuihuang microstructuralevolutionalongthenicrmovsteelweldedjointsinducedbylowcyclefatiguedamage AT mingliangzhu microstructuralevolutionalongthenicrmovsteelweldedjointsinducedbylowcyclefatiguedamage AT fuzhenxuan microstructuralevolutionalongthenicrmovsteelweldedjointsinducedbylowcyclefatiguedamage |