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Pb-Sn共晶合金超塑变形时晶粒三维重排物理模型的建立
The Physical Model of Three Dimensional Grain Rearrangement in Pb-Sn Eutectic Alloy during Superplastic Deformation
【摘要】 利用动态定点观察和对界面易动性的测试,发现 Pb—62Sn 双相(α+β)合金的超塑性变形是借助晶粒三维重排和转动而实现晶粒沿拉伸轴方向重新排列的过程。由于α相和β相晶粒易动性的程度不同,导致各自的重排方式有很大差别。文中提出了一个双相合金超塑性变形晶粒三维重排模型。作者认为:在超塑性变形初期,晶界滑动主要是以晶界位错运动实现的,当晶界产生微空洞时,则由晶界位错运动和晶界空洞运动共同实现的;不同界面对晶界滑动的协调方式不同:β/β界面是以晶界迁移的方式协调,而α/β界面则以β相一侧晶界附近区域的塑性变形方式进行协调。
【Abstract】 By investigating the movability of every kind of grain bondaries and the dynamic process of the superplastic deformation in situ it is found that the microprocess of the superplastic tension of Pb-62Sn duplex alloy (α+β) is realized by three-dimensional grain rearrangement and turning by means of grain bondary sliding (GBS).Grains of different phases rearrange in different ways because of the dissimilarity of movabilities between the two phaces.A model is established to describe the three-dimensional grain rearrangement in duplex alloy during superplastic deformation.Two points are put forward that are as follows:(1)GBS is carried out by the motion of GB dislocations in initial period of the deformation and the movement of cavities as well when they are formed in GB,(2)The accommodation to β/β boundary which is conducted by GB migration disagrees with that to α/β one which is achieved by plastic deformationin the mantle area of β grain.
【Key words】 superplasticty; grain boundary sliding; three dimensional grain rearrangement;
- 【文献出处】 金属科学与工艺 , 编辑部邮箱 ,1990年02期
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