Low Cycle Fatigue Characteristics of Oxygen-Free Copper for Electric Power Equipment
| Autor: | Takuma Tanaka, Yuya Shimada, Togo Sugioka, Tatsuya Kobayashi, Yuichiro Kamakoshi, Hiromitsu Watanabe, Ikuo Shohji |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Technology
Oxygen-free copper Recrystallization (geology) Materials science chemistry.chemical_element 02 engineering and technology low cycle fatigue properties Plasticity 01 natural sciences Article Stress (mechanics) fatigue damage behavior 0203 mechanical engineering Residual stress 0103 physical sciences Ultimate tensile strength General Materials Science Composite material oxygen-free copper tensile properties EBSD analysis 010302 applied physics Microscopy QC120-168.85 QH201-278.5 Engineering (General). Civil engineering (General) Copper TK1-9971 Grain growth 020303 mechanical engineering & transports Descriptive and experimental mechanics chemistry Electrical engineering. Electronics. Nuclear engineering TA1-2040 |
| Zdroj: | Materials; Volume 14; Issue 15; Pages: 4237 Materials Materials, Vol 14, Iss 4237, p 4237 (2021) |
| ISSN: | 1996-1944 |
| DOI: | 10.3390/ma14154237 |
| Popis: | The effect of heat treatment on tensile and low cycle fatigue properties of the oxygen-free copper for electric power equipment was investigated. The heat treatment at 850 °C for 20 min, which corresponds to the vacuum brazing process, caused the grain growth and relaxation of strain by recrystallization, and thus, the residual stress in the oxygen-free copper was reduced. The tensile strength and 0.2% proof stress were decreased, and elongation was increased by the heat treatment accompanying recrystallization. The plastic strain in the heat-treated specimen was increased compared with that in the untreated specimen under the same stress amplitude condition, and thus, the low cycle fatigue life of the oxygen-free copper was degraded by the heat treatment. Striation was observed in the crack initiation area of the fractured surface in the case of the stress amplitude less than 100 MPa regardless of the presence of the heat treatment. With an increase in the stress amplitude, the river pattern and the quasicleavage fracture were mainly observed in the fracture surfaces of the untreated specimens, and they were observed with striations in the fracture surfaces of the heat-treated ones. The result of the electron backscattered diffraction (EBSD) analysis showed that the grain reference orientation deviation (GROD) map was confirmed to be effective to investigate the fatigue damage degree in the grain by low cycle fatigue. In addition, the EBSD analysis revealed that the grains were deformed, and the GROD value reached approximately 28° in the fractured areas of heat-treated specimens after the low cycle fatigue test. |
| Databáze: | OpenAIRE |
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