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| A STUDY OF RATE-DEPENDENCE AT ELEVATED TEMPERATURE FOR AN Al-Cu-Mg ALLOY | |
| 作者姓名： | Y.Q.Wu H.J.Shi K.S.Zhang |
| 作者单位： | Key Laboratory of Failure Mechanics，Department of Engineering Mechanics，Tsinghua University，Beijing 100084，China Department of Engineering Mechanics，North-Western Polytechnical University，Xi'an 710072，China，Key Laboratory of Failure Mechanics，Department of Engineering Mechanics，Tsinghua University，Beijing 100084，China，Department of Engineering Mechanics，North-Western Polytechnical University，Xi'an 710072，China |
| 基金项目： | 国家重点基础研究发展计划(973计划)，中国博士后科学基金，教育部重点项目 |
| 摘 要： | The hot deformation of an Al-Cu-Mg alloy was studied in the two temperature ranges (room temperature-300℃ and 400℃-480℃). The rate-independent flow curves are typical of elasto-plastic response with significant work hardening followed by strain softening below 300℃. Similar dislocation structures with high density tangled into grain interiors were observed by TEM, which suggests that the process of obstacles arresting mobile dislocations results in this macroscopically rate-independence. At 400-480℃, all rate dependent flow behaviors characterized by a continuous softening after an initial work hardening at a small plastic strain show large tensile elongations. Long dislocation segments around the second phases infer their good mobility to climb across obstacles. Grain boundary morphology observed by TEM suggests that the capacity of the grain boundaries to absorb the dislocations sensitively accounts for the rate-dependent mechanical properties. |
A STUDY OF RATE-DEPENDENCE AT ELEVATED TEMPERATURE FOR AN Al-Cu-Mg ALLOY |
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| Y.Q.Wu,H.J.Shi,K.S.Zhang.A STUDY OF RATE-DEPENDENCE AT ELEVATED TEMPERATURE FOR AN Al-Cu-Mg ALLOY[J].Acta Metallurgica Sinica(English Letters),2004,17(4). | |
| Authors: | YQWu HJShi KSZhang |
| Affiliation: | 1. Key Laboratory of Failure Mechanics, Department of Engineering Mechanics, Tsinghua University,Beijing 100084, China;Department of Engineering Mechanics, North-Western Polytechnical University, Xi'an 710072, China 2. Key Laboratory of Failure Mechanics, Department of Engineering Mechanics, Tsinghua University,Beijing 100084, China 3. Department of Engineering Mechanics, North-Western Polytechnical University, Xi'an 710072, China |
| Abstract: | The hot deformation of an Al-Cu-Mg alloy was studied in the two temperature ranges (room temperature-300℃ and 400℃-480℃). The rate-independent flow curves are typical of elasto-plastic response with significant work hardening followed by strain softening below 300℃. Similar dislocation structures with high density tangled into grain interiors were observed by TEM, which suggests that the process of obstacles arresting mobile dislocations results in this macroscopically rate-independence. At 400-480℃, all rate dependent flow behaviors characterized by a continuous softening after an initial work hardening at a small plastic strain show large tensile elongations.Long dislocation segments around the second phases infer their good mobility to climb across obstacles. Grain boundary morphology observed by TEM suggests that the capacity of the grain boundaries to absorb the dislocations sensitively accounts for the rate-dependent mechanical properties. |
| Keywords: | rate dependence elevated temperature dislocations grain boundary |
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