Dislocation motion induced by pulse current in Ti/Al bimetal composite observed by in-situ TEM

The in-situ transmission electron microscopy (TEM) was applied to investigate the effect of pulse current on the dislocation evolution of Ti/Al bimetal composite sheet. By comparison of electrical in-situ and thermal in-situ experiment, the dislocation moving along the electron wind direction were observed in the Al matrix and interface region. The results revealed that the dislocation behavior of the Al matrix and interface were affected not only by Joule heating effect, but also by non-thermal effect. In contrast, the dislocation motion of the Ti matrix was more significantly affected by Joule heating effect. The effect of the pulse current on dislocation evolution can be divided into three stages. When the current was <0.8 mA, the current has little effect on the dislocation of Ti/Al bimetal composite sheet. When the current was between 0.8 mA and 2.2 mA, the dislocation motion appeared to be enhanced by current. But the effect was confined, and the dislocation pile up did not improve. When the current is >2.4 mA, the dislocation motion was promoted significantly due to the pulse current, and the dislocation entanglements were facilitated to open. The dislocation density of Ti/Al bimetal composite sheet decreased.