7055铝合金晶界η相回归阶段的粗化动力学

Coarsening kinetics of grain boundary precipitates in 7055 aluminium alloy

采用透射电镜、拉伸试验、剥落腐蚀试验等手段,研究7055铝合金在回归时效阶段的晶界η相形貌、尺寸、间距及其粗化动力学行为,以及对最终材料性能的影响。结果表明:随着回归温度的升高或回归时间的延长,晶界η相不断粗化,间距也不断增大;且回归温度越高,晶界η相粗化速率越快。在本实验条件下,该合金晶界η相的粗化激活能Q=1.13 eV,据此建立晶界相粗化动力学模型。

The morphology and coarsening kinetics of grain boundary precipitates （η） in the regression aging stage of 7055 aluminium alloys were studied by transmission electron microscopy （TEM）, and the corresponding effects on the mechanical property and corrosion resistance were measured by tensile tests and exfoliation corrosion tests. The results show that the grain boundary precipitates （η） are coarsened and the inter-space increases with the retrogression temperature or retrogression time increasing. The coarsening rate ofη precipitates increases with retrogression temperature increasing. The coarsening activation energy is 1.13 eV, and a modified coarsening kinetics model of grain boundary precipitates was proposed.