METALLIC GLASSES
,Why metallic glasses?
Structural potential Design challenge
Metallic glasses combine metallic bonding The central challenge is not to maximize a
with the absence of long-range crystalline single property. For structural use, the material
order. This structure enables very high elastic must resist yielding while also preventing a
limits and strengths, surfaces with good wear crack or shear band from becoming unstable.
resistance, and, in some compositions, This presentation examines how composition,
remarkably high fracture toughness. structural state, and processing control that
balance.
The goal is not to choose between strength and toughness: it is to create mechanisms that
preserve both when the component contains real defects.
,What is a metallic glass?
A metallic glass is a metal alloy solidified without
macroscopic crystallization. Its atoms remain
densely packed but lack long-range translational
periodicity. Achieving the glassy state requires
suppressing crystal nucleation and growth during
cooling, which demands an appropriate
composition and compatible thermal history.
Didactic comparison between a periodic crystalline arrangement and an
amorphous metallic structure.
, Amorphous versus crystalline structure
The absence of grains changes the dominant deformation and fracture mechanisms. The table
summarizes key differences in mechanical response.
Aspect Crystalline metal Metallic glass
Aspect Crystalline metal Metallic glass
Atomic order Periodic, with grains No long-range order
Plasticity carriers Dislocations Local transformations and shear bands
Strain hardening Often present Generally limited in the monolithic state
Defect sensitivity Depends on microstructure Can be high when deformation localizes
,Why metallic glasses?
Structural potential Design challenge
Metallic glasses combine metallic bonding The central challenge is not to maximize a
with the absence of long-range crystalline single property. For structural use, the material
order. This structure enables very high elastic must resist yielding while also preventing a
limits and strengths, surfaces with good wear crack or shear band from becoming unstable.
resistance, and, in some compositions, This presentation examines how composition,
remarkably high fracture toughness. structural state, and processing control that
balance.
The goal is not to choose between strength and toughness: it is to create mechanisms that
preserve both when the component contains real defects.
,What is a metallic glass?
A metallic glass is a metal alloy solidified without
macroscopic crystallization. Its atoms remain
densely packed but lack long-range translational
periodicity. Achieving the glassy state requires
suppressing crystal nucleation and growth during
cooling, which demands an appropriate
composition and compatible thermal history.
Didactic comparison between a periodic crystalline arrangement and an
amorphous metallic structure.
, Amorphous versus crystalline structure
The absence of grains changes the dominant deformation and fracture mechanisms. The table
summarizes key differences in mechanical response.
Aspect Crystalline metal Metallic glass
Aspect Crystalline metal Metallic glass
Atomic order Periodic, with grains No long-range order
Plasticity carriers Dislocations Local transformations and shear bands
Strain hardening Often present Generally limited in the monolithic state
Defect sensitivity Depends on microstructure Can be high when deformation localizes
