溶质元素及其偏聚对六方系金属层错能的影响

Influence of Solute and Solute Segregation on the Stacking Fault Energy in hcp Metals

利用层错能的热力学模型对AZ31,AZ61,AZ91等六方系合金的层错能进行了计算,推导出溶质元素含量及偏聚对层错能影响的理论表达式。计算结果表明:该热力学模型适用于六方系合金层错能的计算,计算的结果与实验相符。其中AZ31,AZ61,AZ91合金的基面层错能在373K时都为45mJ/m2。镁合金层错能随着温度的升高逐渐降低,化学自由能对层错能的影响占主导地位。Al元素有降低镁合金层错能的作用,随着固溶于镁基体中Al含量的增加,合金的层错能降低。合金元素在层错区域内的偏聚对层错能造成的影响也不容忽视,溶质元素Al的偏聚增加了镁合金的层错能。

Based on the thermodynamic model of stacking fault energy（SFE）,the SFE of hcp alloys AZ31,AZ61 and AZ91 has been calculated.The equation of the influence of solute concentration and its segregation on the SFE has also been established.The result shows that the thermodynamic model is fitted perfectly in the hcp alloys and the calculated result is generally consistent with the experimental.The SFE of AZ31,AZ61 and AZ91 is 45 mJ/m2 at 373 K.The SFE of magnesium alloy is decreased gradually with the temperature increasing.The chemical free energy is the key factor influencing SFE.In addition,aluminum can reduce the stacking fault energy of magnesium alloy.The SFE is decreased with increasing the content of aluminum solving into the base magnesium alloy.And the influence of segregation on the SFE cannot be ignored.Al segregation can increase the SFE of magnesium alloy.