摘要
The AA7150 aluminum alloy was compressed to various strains at strain rate of 10 s（-1） and temperatures of 300 °C and 450 °C, respectively. Flow stress behavior, substructure evolution, morphology and spatial distribution of precipitates were studied based on differential scanning calorimetry analysis and transmission electron microscope observation. The results showed that dynamic flow softening occurs during hot deformation. The main softening mechanism could be concluded as dynamic recovery at 300 °C and continuous dynamic recrystallization at 450 °C. The clear heterogeneous spatial distributions of precipitates are found during deformation and enhanced with increased strain. Higher contents of Cu in T phases are found at 450 °C than at 300 °C, which present a transformation process from T phases to S phases as well. The associated evidence of dynamic precipitation on dislocations and particle-stimulated nucleation, as well as the detailed microstructural inherited relationship and morphological texture（particles preferred orientation） were characterized.
在温度分别为300°C和450°C条件下对AA7150铝合金进行高应变速率(10 s^(-1))热压缩实验。结合差热分析和透射电子显微镜对其不同应变下热变形过程流变行为、亚结构演变及析出相形貌和空间分布进行了系统研究。研究结果表明:AA7150铝合金热变形过程发生了流变软化,在300°C条件下主要软化机制是动态回复,而450°C条件下为连续动态再结晶;合金热变形过程中η相(300°C)及Al_3Zr粒子(450°C)随应变的增加分布不均匀;T相中的铜含量随温度升高而增加且有从T相向S相转变的趋势,且随变形量的增加逐渐呈线性排列;显微组织还显示了动态析出及粒子诱发形核再结晶直接相关的形貌特征。
基金
Project(20130161110007) supported by the Doctoral Program of the Ministry of Education,China
Project(CX2013B128) supported by Hunan Provincial Innovation Foundation for Postgraduate,China
Project(201306130021) supported by the Chinese Scholarship Council
