One of the reasons is that this has been identified as the first paper to report that bulk glassy alloys in simple ternary Cu-based alloy systems can be formed by the copper mold casting process. As a result of this process, the Cu-based bulk glassy alloys exhibit very high tensile and compressive strength combined with distinct plastic elongation. The extension of alloy component to quaternary and more multi-component had been expected to produce various Cu-based bulk glassy alloys with good mechanical properties. It was also noticed that the strength level exceeded 2,000 Mpa. This is much higher than the previous data (800 to 1,800 MPa) for Mg-, Pd-, and Zr-based bulk glassy alloys. In addition, the Cu-Zr-Ti glassy alloys have some anomalous points, i.e., (l) a high glass-forming ability in spite of a small supercooled liquid region forming before crystallization; (2) the formation of a mixed structure of glassy and nanoscale precipitates in as-cast state; and (3) high strength and high ductility even in a mixed-structure state.

The paper provides the first success in synthesizing Cu-based bulk glassy alloys exhibiting high glass-forming ability as well as good mechanical properties.

  What were some of the circumstances that led you to do this research?

We were aiming to develop a new bulk glassy alloy with much higher tensile strength in an alloy system where the major component is less expensive metal. Furthermore, we were searching for a possibility of developing a bulk glassy alloy with high strength combined with good ductility in a mixed state of glassy and nanoscale crystalline or quasicrystalline precipitates.

  Could you summarize the significance of your paper in layman's terms?

This paper has dealt with the first successful data on the bulk glassy alloys exhibiting high tensile strength above 2,000 MPa in a new, less expensive, Cu-based alloy system.

Professor Akihisa Inoue, Director
Tohoku University Institute for Materials Research,
Aoba-Ku Sendai, Japan