Advances in Bulk Metallic Glasses
A special issue of Materials (ISSN 1996-1944).
Deadline for manuscript submissions: closed (31 October 2011) | Viewed by 21844
Special Issue Editors
Special Issues, Collections and Topics in MDPI journals
Special Issues, Collections and Topics in MDPI journals
Special Issue Information
Dear Colleagues,
Bulk metallic glasses (BMGs) are currently on the cutting edge of Materials Science research. Easy bulk glass forming alloys are usually multicomponent eutectic or near eutectic liquid compositions with high viscosities and depressed melting temperatures that result in reduced critical cooling rates required for suppression of crystal formation.
For about two decades after the discovery of the first glassy alloy quenched from the liquid in 1960, the critical cooling rate for suppression of crystallisation was extremely high (of the order of 106 K/s), limiting the sample dimensions to less than 100 μm and restricting applications to a few areas such as magnetic devices and sensors. In the 80’s, an improvement of the maximum size of glassy specimens had been achieved for few alloys using fluxing techniques, bringing down the critical cooling rates to about 104K/s. However, the trend changed in the early 90’s and bulk metallic glasses emerged as an important and promising new class of materials. Since then, a large number of bulk alloys has been quenched to a glassy state with thickness reaching several centimeters and critical cooling rates sometimes as low as 1 K/s. This dramatic improvement in the glass formability was related to alloys having three main features, i.e. multi-component systems, significant atomic size ratios above 12% between their components and negative heats of mixing.
The disordered atomic structure of bulk metallic glasses results in various remarkable properties, such as high mechanical strength up to 5 GPa, elasticity up to 2% strain, good corrosion and wear resistance and excellent soft magnetic properties. The combination of their unique properties with their good formability through viscous flow in the supercooled liquid state, and their near-net-shape casting ability has led to several new applications including reinforcement for high-performance sports equipment, micromotors, springs, armor devices, biomedical implants and ornaments. However, the field of bulk metallic glasses is believed to possess high potential for further development.
Prof. Dr. Alain. R. Yavari
Dr. Konstantinos Georgarakis
Guest Editors
Keywords
- supercooled liquids
- amorphous metals
- glass-forming ability
- liquid alloys
- rapid quenching
- copper mold casting
- fluxing
- critical cooling rate
- glass transition
- eutectic alloys
