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Vol.52, No.4, 283 ~ 292, 2014
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| Title |
| High Cycle Fatigue and Fatigue Crack Propagation Behaviors of Modified A7075-T73 Alloy |
| 김관영 Gwan Yeong Kim , 김규식 Kyu Sik Kim , 박중철 Joong Cheol Park , 김세광 Shae K Kim , 윤영옥 Young Ok Yoon , 이기안 Kee Ahn Lee |
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| Abstract |
| The high cycle fatigue and fatigue crack propagation behaviors of the recently developed modified A7075-T73 alloy are investigated. This alloy is manufactured using Eco-Mg (including CaO) instead of a magnesium element. The alloy consists of an Al matrix, Al2CuMg, MgZn2, minute amounts of Ca phases and reduced Fe-based intermetallic or oxide. The modified A7075 alloy exhibits superior strengths (YS: 492 MPa, TS: 548 MPa) with a similar elongation (12.8%) compared with the conventional A7075. Furthermore, the high cycle fatigue properties are significantly improved (fatigue limit of 330 MPa at 107 cycles) compared with those of the conventional alloys. The fatigue crack propagation rate of the modified A7075 is similar or somewhat lower (higher resistance) than those of the conventional alloys. The superior tensile and fatigue properties of the modified A7075-T73 alloy are primarily attributed to the grain size refinement, evenly distributed strengthening phases (MgZn2 precipitates), and reduction of detrimental effects of the Fe- intermetallic phases and oxides. |
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| Key Words |
| Alloys, Modified A7075-T73, Extrusion, Fatigue, Scanning Electron Microscopy, SEM |
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