Insight into bending deformation behaviors of a Zr-based metallic glass thin beam for self-expanding aortic stent applications.

Abstract

The mechanical reliability of self-expanding stents critically depends on the ability of their constituent beam elements to sustain large bending deformation without instability. While NiTi alloys are widely used, their processing complexity and transformation-related uncertainties motivate the exploration of alternative metallic systems. Zr-based metallic glasses (MGs), which combine high elastic recoverability with structural homogeneity, offer a compelling but insufficiently understood option under bending-dominated loading. In this study, the bending deformation behavior of a 0.25 mm-thick Zr₆₁Ti₂Cu₂₅Al₁₂ (ZT1) high-toughness MG beam is investigated under conditions relevant to miniaturized stent architectures. Emphasis is placed on precisely capturing the onset of yielding under bending, unraveling the two-stage evolution and underlying mechanisms of shear-band-mediated plasticity, and clarifying the size-dependent nature of plastic deformation stability in MG beams. The results reveal a distinct bending-specific deformation response that differs fundamentally from uniaxial loading, characterized by thickness-sensitive shear-band organization and enhanced resistance to shear localization. By linking these observations to fracture-mechanics considerations, this study provides a mechanistic framework for understanding why thin MG beams can accommodate large bending strains without catastrophic failure. The insights gained establish a foundation for the rational design of MG components in bending-dominated biomedical devices.