It has been known for decades that the application of pulsed direct current can significantly enhance the formability of metals. However, the detailed mechanisms of this effect have been difficult to separate from simple Joule heating. Here, we study the electroplastic deformation of Ti–Al (7 at.% Al), an alloy that is uniquely suited for uncoupling this behaviour because, contrary to most metals, it has inherently lower ductility at higher temperature. We find that during mechanical deformation, electropulsing enhances cross-slip, producing a wavy dislocation morphology, and enhances twinning, which is similar to what occurs during cryogenic deformation. As a consequence, dislocations are prevented from localizing into planar slip bands that would lead to the early failure of the alloy under tension. Our results demonstrate that this macroscopic electroplastic behaviour originates from defect-level microstructural reconfiguration that cannot be rationalized by simple Joule heating.

几十年来，已知脉冲直流电的施加可以显着增强金属的可成形性。但是，这种作用的详细机理很难与简单的焦耳加热分开。在这里，我们研究了Ti-Al（7at。％Al）的电塑性变形，该合金特别适合于解除这种行为，因为与大多数金属相反，它在高温下固有地具有较低的延展性。我们发现，在机械变形过程中，电脉冲增强了交叉滑动，产生了波浪状的位错形态，并增强了孪晶，这与低温变形过程中发生的现象相似。结果，防止了位错局限在平面滑带中，这将导致合金在张力下过早失效。