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采用扫描电子显微镜（SEM）对Zn-Al合金超塑变形时的相界滑移进行了观察,并深入研究了Zn粉和Al粉压制烧结中Zn和Al相界间的扩散行为.实验结果表明,Zn粉和Al粉通过扩散烧结可形成共析组织,两者间的扩散行为是Kirkendall效应的一种显现,即Zn能溶入Al中而Al却几乎不能溶入Zn,在扩散烧结过程中形成的共析组织是由Zn和Al相界间形成的扩散溶解层α＇在冷却过程中转变而来.最后在实验结果的基础上提出了一种Zn-5Al共晶合金的超塑性变形模型:Zn-5Al共晶合金的超塑变形机制是α和β相界面滑移,而α和β相界间形成的扩散-溶解层α＇对相界滑移起控制作用,含缺陷的不饱和的扩散-溶解层α＇与β相结合较弱容易滑移,而当扩散-溶解层α＇变厚并达到动态饱和时则不利于滑移的进行.
The phase boundary slip of Zn-Al alloy during superplastic deformation was observed by scanning electron microscopy (SEM), and the diffusion behavior between Zn and Al phases in Zn powder and Al powder was studied in depth. The experimental results show that , Zn powder and Al powder can form eutectoid structure through diffusion sintering. The diffusion behavior between Zn powder and Al powder is a manifestation of Kirkendall effect. That is, Zn can dissolve into Al and Al almost does not dissolve into Zn. During diffusion sintering The formation of eutectoid structure is formed by the diffusion between the Zn and Al interfacial dissolution dissolved layer α ’in the cooling process of transformation from the experimental results based on the proposed Zn-5Al eutectic alloy superplastic deformation model : The superplastic deformation mechanism of the Zn-5Al eutectic alloy is the slip between the α and β phases, while the diffusion-dissolution layer α ’formed between the α and β phases intercepts the slip of the phase boundary, and the defect containing unsaturation The diffusion-dissolution layer α ’is weak and easy to slip with the combination of β, while the diffusion-dissolution layer α’ becomes thick and reaches dynamic saturation, which is unfavorable to the sliding.