1. BULK METALLIC GLASSES
MATE 310/350
Independent Inquiry
Cal Poly Materials Engineering
RHYS GILMORE

2. MATERIALS SCIENCE BACKGROUND
Theoretical strength of a material is significantly
higher than what is observed in reality.
 Why?
 Dislocations and grain boundaries provide zones for a material to fracture
 Theoretical strength is exclusively a property of atomic bonding

3. BACKGROUND
What if engineers could take advantage of the
inherent strength and ductility of metals,
without weakening the material with grain
boundaries and dislocations?

4. WHAT IS A BULK METALLIC GLASS?
BULK:
Material that can be
manufactured to a thickness of
at least one millimeter.
METALLIC:
Composed of at least one
metallic element.
GLASS:
The microstructure of the
material is amorphous,
rather than crystalline.

5. ATTRACTIVE PROPERTIES
 High hardness, yield strength
 Lack of microstructural features gives good corrosion resistance
 Glass Transition Temperatures allows for thermoplastic forming capabilities
 Magnetism, Resistivity independent of temperature
Significant Advantages:
 BMGs are strong, corrosion resistant materials that are easily formable.
 Some alloys have unique magnetic, polish, or biocompatible properties that allow for
use in niche markets.

6. ATTRACTIVE PROPERTIES

7. UNATTRACTIVE PROPERTIES
 Current high cost of material and processing limits applications.
 Severe localization of plastic flow produces zero ductility in tension.
 Unstable at high temperatures due to crystallization or low viscosity.
 Fracture toughness can be very low.
Significant Disadvantages:
 BMGs are expensive and difficult to manufacture.
 Brittle failure is a significant concern, especially for large parts.

8. UNATTRACTIVE PROPERTIES

9. PROCESSING
Common Production Methods
 Extremely fast cooling
 Vapor Deposition
 Solid-state Reactions
 Ion Irradiation
 Mechanical Allloying

10. EXTREMELY FAST COOLING WITH MELT SPINNING

11. FAILURE MECHANISM: SHEAR BANDING

12. CURRENT APPLICATIONS
Most are niche applications, focusing on biocompatibility, springiness, or
magnetic properties.
 Transformers
 Electronic Article Surveillance
 Sports Equipment
 Biomedical Implants

13. TOUGHEST MATERIAL IN THE WORLD
 Research suggests that BMGs are capable
of incredible toughness.
 Toughest material in the world is a
Palladium based BMG.

14. BMG USE AS A COMPOSITE
Research by Dr. Kevin Laws suggests that BMGs might find the best use as a Metal Matrix Composite
(MMC).
 Forgeable Carbon Fiber reinforced MMC (Mg, Cu, Y)
 Amorphous structure obtained with Melt Spinning

15. THE FUTURE FOR BULK METALLIC GLASSES
As Pure BMG:
 Precision Tooling
 Springs and Clubs
 Information storage
 Fashion Items
As a Metal Matrix Composite (MMC)
 Aerospace
 Automotive

16. REFERENCES
Ashby, M.F.
Metallic glasses as structural materials
Scripta Materialia, 2005
Demetrious, Marios D.
A damage-tolerant glass
Nature Materials, 2011
Laws, Kevin J.
Supercooled liquid fusion of carbon fibre-bulk metallic glass composites with superplastic forming
properties
Scripta Materialia, 2015