α黄铜爆炸、滚压强化后表面层组织结构的TEM研究

TEM Investigation on the Surface Strengthened Layer of α—Brass after Explosive or Rolled Strengthening

与喷丸强化相似,α黄铜经爆炸强化后表面层因高速应变而形成显微孪晶栅栏。仔细分析这些孪晶的构造,可以发现它们内部包含了密集的趋近某一方向的螺位错线和大量重叠层错。孪晶栅栏把α晶粒分割成许多小块,块内位错密度很高,但没有胞状结构出现。α黄铜经滚压强化后表面层内没有发现孪晶栅栏,只看到具有方向性的螺位错趋于紧密排列,并显示出将要形成孪晶亚结构的倾向,因此,对α黄铜而言,强化方式不同,强化层内的组织结构是有着明显差别的。

Microtwin paling will be formed in the strengthened layer of a--brass after explosive strengthening. Mi-crotwin is composed by the overlapping of stacking faults or by the clustering of screw dislocations with the same orientation. Twin palings divide a grain into many small areas. Although high dense dislocations are locat-ed in the areas, no dislocation cells can be observed in them. After rolled strengthening twin paling can not be found in the strengthened layer. Only screw dislocation lines tend to array in a sheaflike manner and they have a tendency to form a twin substructure. Therefore different strengthening methods result in different substruc- tures in the strengthened layer of a--brass.