Transformation-mediated ductility in CuZr-based bulk metallic glasses

Area of Science:

• Materials Science
• Mechanical Engineering
• Condensed Matter Physics

Background:

• Bulk metallic glasses (BMGs) typically exhibit brittle failure under quasistatic tensile loading due to shear softening and localized plastic strain in shear bands.
• Achieving macroscopic tensile ductility and work hardening in BMGs at room temperature has remained a significant challenge.

Discussion:

• The study introduces novel CuZr-based BMGs that undergo polymorphic precipitation of nanocrystals during tensile deformation.
• These precipitated nanocrystals subsequently twin, a process that impedes shear band formation and promotes macroscopic plastic deformation.
• This mechanism is linked to a deformation-induced softening of the instantaneous shear modulus.

Key Insights:

• Development of CuZr-based BMGs exhibiting significant plastic strain and work hardening under quasistatic tension.
• Discovery of a novel deformation mechanism involving nanocrystal precipitation and twinning in BMGs.
• Demonstration that structural heterogeneities can effectively suppress brittle failure in metallic glasses.

Outlook:

• The findings suggest a new pathway for designing ductile BMGs with enhanced mechanical properties.
• The identified deformation mechanism may be applicable to other classes of metallic glasses, broadening their potential applications.
• Further research could explore optimizing nanocrystal precipitation and twinning for tailored material performance.