The important benefits of ultrafine-grained (UFG) alloys for various applications stem from their enhanced superplastic properties. However, decreasing the temperature of superplasticity and providing superplastic forming at lower temperatures and higher strain rates is still a priority. Here, we disclose, for the first time, the mechanism by which grain boundary sliding and rotation are enhanced, when UFG materials have grain boundary segregation of specific alloying elements. Such an approach enables achieving superplasticity in commercial Al alloys at ultralow homologous temperatures below 0.5 (i.e. below 200°C), which is important for developing new efficient technologies for manufacturing complex-shaped metallic parts with enhanced service properties.

超细晶粒 (UFG) 合金在各种应用中的重要优势源于其增强的超塑性性能。然而，降低超塑性的温度并在较低的温度和较高的应变率下提供超塑性成形仍然是一个优先事项。在这里，我们首次公开了当 UFG 材料具有特定合金元素的晶界偏析时，晶界滑动和旋转增强的机制。这种方法能够在低于 0.5（即低于 200°C）的超低同源温度下实现商用铝合金的超塑性，这对于开发用于制造具有增强使用性能的复杂形状金属零件的新高效技术非常重要。