Near-superplastic behavior of a body-centered cubic Zr50Ti35Nb15 multi-principal element alloy via dynamic recrystallization

Near-superplastic and superplastic behaviors are rarely observed in body-centered-cubic (bcc) multi-principal element alloys (MPEAs). Here, we show that a cold-rolled bcc Zr50Ti35Nb15 medium-entropy alloy (MEA) exhibits superior tensile ductility with the maximum elongation up to 200% - a near-superplastic behavior - at elevated temperatures in the temperature range of 400-500 degrees C. The high-density dislocations induced by the cold rolling lead to a high driving force for dynamic recrystallization, enabling grain-boundary sliding to relieve the stress concentration during the tensile test and enhancing its tensile ductility. Meanwhile, dislocation slips further facilitate the shear strains of coarse grains. Our study demonstrates near-superplastic behavior in bccMPEAs and suggests an effective route to achieve enhanced ductility in typically brittle bcc MPEAs through dynamic recrystallization.

Automated summary

In this study, it was found that a cold-rolled bcc Zr50Ti35Nb15 medium-entropy alloy exhibited superior tensile ductility with near-superplastic behavior at elevated temperatures. The high-density dislocations induced by cold rolling facilitated dynamic recrystallization, which relieved stress concentration and enhanced its tensile ductility. This study demonstrates the near-superplastic behavior in bccMPEAs and suggests an effective route to enhance ductility in typically brittle bcc MPEAs through dynamic recrystallization.