A Multiple Twin-Roller Casting Technique for Producing Metallic Glass and Metallic Glass Composite Strips.

To date it has not been possible to produce metallic glass strips with a thickness larger than 150 m via single-roller melt spinning technique, and it remains challenging to produce thick metallic glass strips. In this work, a multiple twin-roller casting technique is proposed for producing thick metallic glass and metallic glass composite strips. A triple twin-roller casting device, as a specific case of the multiple twin-roller, was designed and manufactured. The triple twin-roller device possesses a high cooling rate and involves a long contact time between the melt and the strip, which makes it an efficient technique for producing metallic glass strips that avoids crystallization, although the solidification temperature ranges of metallic glasses are as wide as several hundred Kelvins. The two prepared metallic glass (MG) strips are in a fully amorphous state, and the MG strip shows excellent capacity of stored elastic energy under 3-point bending. Furthermore, the Ti-based metallic glass composite strip produced via the triple twin-roller casting exhibits a novel microstructure with much finer and more homogenously orientated -Ti crystals, as compared with the microstructure of metallic glass composites produced by the common copper mold casting technique.