Deformation Twinning

Study finds bcc Nb-Ti and Nb-Ta-Ti-Hf alloys stay tough at 20 kelvin

Researchers examined a medium-entropy alloy, Nb45Ta25Ti15Hf15, alongside a simpler binary Nb70Ti30 alloy, testing their mechanical response at cryogenic temperatures down to 20 K. Using density functional theory, molecular dynamics with a machine-learning potential, and tensile experiments, they tracked how deformation shifts from dislocation glide to twinning as temperature drops, and assessed whether this shift affects the ductile-to-brittle transition.