Al-Cu-Mg-Ag耐热铝合金高温蠕变行为  

CREEP BEHAVIOR OF Al-Cu-Mg-Ag HEAT-RESISTANT ALLOY AT ELEVATED TEMPERATURE

作　　者：刘晓艳[1] 潘清林[1,2] 陆智伦[1] 曹素芳[1] 何运斌[1] 李文斌[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中南大学有色金属材料科学与工程教育部重点实验室,长沙410083

出　　处：《金属学报》2011年第1期53-60,共8页Acta Metallurgica Sinica

基　　金：中南大学优秀博士学位论文扶植基金资助项目2008yb012~~

摘　　要：在100—210℃和150—300 MPa的条件下,研究了Al-5.3Cu-0.8Mg--0.5Ag--0.3Mn--0.15Zr耐热铝合金的蠕变行为,探讨了时效状态对合金高温性能的影响.结果表明:在相同蠕变条件下,欠时效态合金的稳态蠕变速率远远低于峰时效态合金.在210℃/200 MPa下,欠时效态合金的蠕变断裂时间为75 h,而峰时效态合金的蠕变断裂时间仅为21 h.蠕变过程中,合金中的析出相长大.峰时效态合金中析出相尺寸的增大速率高于欠时效态合金.欠时效态合金中还发生了动态析出,这些细小的析出相在蠕变过程中阻碍了位错的运动,使得合金蠕变速率降低.在100—150℃下合金的稳态蠕变速率保持在较低水平.当温度升高到180℃时,合金的稳态蠕变速率急剧增大.合金稳态蠕变速率随着蠕变温度的升高和应力的提高均有增大趋势,3者之间的关系可用一本构方程来表示,其表观激活能为102 kJ/mol.The creep behaviors of heat-resistant alloy Al-5.3Cu-0.8Mg-0.5Ag-0.3Mn-0.15Zr （Al-Cu-Mg-Ag） were studied in a temperature range of 100—210℃and a load range of 150—300 MPa, and the effect of aging on the properties of Al-Cu-Mg-Ag alloy at elevated temperatures was also investigated. The results show that the steady creep rate of the under-aged alloy is much lower than that of the peak-aged alloy at the same creep conditions. The creep fracture time is 75 h for the under-aged Al-Cu-Mg-Ag alloy at 210℃/200 MPa, while that for the peak-aged alloy is only 21 h. The precipitates grow gradually during the creep process and the growth rate in the peak-aged alloy is higher than that in the under-aged alloy. Dynamic precipitation happened in the under-aged alloy. The fine precipitates inhibite the motion of the dislocations during the creep, which leads to lower creep deformation rate compared to the peak-aged alloy. The steady creep rates of the under-aged Al-Cu-Mg -Ag alloy at 100—150℃keep a relatively lower level, but increases to a high level when the creep temperature increased to 180℃. The steady creep rate increased with increasing temperature or stress, which can be described by a constitutive equation with an apparent activation energy of 102 kJ/mol.

关 键 词：AL-CU-MG-AG合金 蠕变 欠时效态 稳态蠕变速率 

分 类 号：TG146.21[一般工业技术—材料科学与工程]