Effect of pre-deformation on aging creep of Al-Li-S4 alloy and its constitutive modeling  

预变形对Al-Li-S4合金时效蠕变的影响规律及其本构建模（英文）

作　　者：王萌[1,2] 湛利华[1,2] 杨有良 阳凌[1,2] 黄明辉[1,2] 

机构地区：[1]中南大学机电工程学院,长沙410083 [2]中南大学高性能复杂制造国家重点实验室,长沙410083

出　　处：《Transactions of Nonferrous Metals Society of China》2015年第5期1383-1390,共8页中国有色金属学报（英文版）

基　　金：Project(2014CB046602)supported by the National Basic Research Program of China;Project(51235010)supported by the National Natural Science Foundation of China

摘　　要：A set of uniaxial tensile creep tests at different pre-deformations, aging temperatures and stress levels were carried out for Al-Li-S4 alloy, and the creep behavior and the effects of pre-deformation on mechanical properties and microstructures were determined under basic thermodynamics conditions of aging forming. The results show that pre-deformation shortens the time of primary creep and raises the second steady-state creep rate. Then, the total creep strain is greater, but in the range of test parameters it is still smaller than that without pre-deformation. In addition, transmission electron microscopy（TEM） observation shows that pre-deformation promotes the formation of T1 phase and θ′ phase and makes them distribute more dispersively, while inhibits the generation of δ′ phase, which leads to the improvement of mechanical properties of the alloy. A unified constitutive model reflecting the effects of aging mechanism, stress levels and different pre-deformations was established. The fitting results agree with the experimental data well.以Al-Li-S4合金为研究对象,开展其在不同预变形量、不同时效温度和试验应力下的单向拉伸蠕变试验,获得Al-Li-S4合金在时效成形基本热力条件下的时效蠕变行为和预变形对其形变、力学性能和显微组织的影响规律。结果表明:试样预变形量越大,蠕变第一阶段持续时间越短,蠕变第二阶段的稳态蠕变速率越大,最终的蠕变应变量越大,但在试验参数范围内仍小于未经预变形处理试样的蠕变应变量;TEM结果显示,引入预变形对T1相和θ′相析出有一定的促进作用并能显著促进析出相的细小弥散分布,同时抑制δ′相的析出,从而改善合金的力学性能。建立了能够反映时效机制、应力和预变形影响的蠕变时效统一本构模型,该模型的拟合结果对实验数据有较好的回归效果。

关 键 词：Al-Li-S4 alloy aging creep PRE-DEFORMATION mechanical properties microstructure constitutive model 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG115.5[金属学及工艺—金属材料]