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采用TEM研究了7A55合金回归过程中晶界析出相的动力学行为。研究结果表明:晶界析出相的粗化遵循“LSW”理论,即晶界相平均尺寸的三次方与回归温度呈线性关系,且晶界相的粗化速率随着回归温度的升高而增大。计算得到7A55合金晶界析出相的粗化激活能为(115.2±1.3)kJ/mol。将7A55铝合金薄板的理论回归制度(190°C,45 min)作为参考,基于“LSW”理论和“等动力学”处理方法,建立了包含Arrhenius方程形式的7A55铝合金晶界相非等温回归模型。当初始晶界相尺寸r0已知时,利用该模型可成功预测非等温回归阶段任意时间点的晶界相平均尺寸r(t)。在此基础上,最终建立了一种7A55铝合金厚板高向组织均匀性的通用表征方法。
The kinetic behavior of precipitated phase in the grain boundary during the regression of 7A55 alloy was studied by TEM. The results show that the coarsening of grain boundary precipitation follows the theory of “LSW”, that is, the cubic of the average grain boundary phase has a linear relationship with the regression temperature, and the coarsening rate of the grain boundary phase increases with the increase of the regression temperature Increase. The coarsening activation energy of precipitated phase of 7A55 alloy was calculated to be (115.2 ± 1.3) kJ / mol. Based on the theory of “LSW ” and “Kinetic ” treatment, the 7A55 aluminum alloy grain boundary containing 7A55 aluminum alloy was established based on the theoretical regression of 7A55 aluminum alloy sheet (190 ° C, 45 min) Non-isothermal regression model. When the initial grain boundary phase size r0 is known, the model can be used to predict the grain boundary average size r (t) at any time during the non-isothermal regression. On the basis of this, a universal characterization method of high-dimensional homogeneity of 7A55 aluminum alloy plate is finally established.