Increasing the cooling rate of Cu mold by liquid alloy coating

Cu mold casting is a common technique of rapid solidification, by which bulk materials (>1mm) can be produced with a cooling rate of 1~1000K/s. In this work, an improved Cu mold casting method with higher cooling rate is proposed. A thin layer of Ga–In–Sn liquid alloy is painted on the surface of Cu mold as a channel of heat flowing between cast sample and mold. The recorded cooling rate of the improved Cu mold exceeds the upper limit of cooling rate of Cu mold and reaches up to 1613K/s. Accordingly, refined microstructure and even a metallic glass layer at surface are obtained in the cast sample via the new method. •A new method of liquid-alloy-lined Cu mold casting is introduced.•Cooling rate of the new method exceeds the upper limit of usual method by 60%.•Refined microstructure in the Fe–P–C sample is achieved by the new method.•Metallic glass surface on the Fe–P–C sample is formed by the new method.