Single crystal growth of cu based shape memory alloy and its thermodynamic analysis

Abstract

Single crystals with a size of 20 mm in diameter and 60 mm in length of Cu-Zn-Al and Cu-Al-Ni alloys were prepared by a modified Bridgeman method which involves the lowering of a cylindrical crucible with a tapered end through a temperature gradient. Theoretical analysis and experimental results both indicate that the single crystal growth rate can be benefited by a crucible with a tapered end and by a larger temperature gradient at the liquid-solid interface of the growing crystal. This study shows that there is a linear relationship between the possible maximum growth rate of the single crystal and the temperature gradient at the liquid-solid interface. Maximum growth rate is 5 mm/h when the temperature gradient is set at 3.8 K/cm. Maximum growth rate can reach up to 40 mm/h if the temperature gradient is set at 26 K/cm.

Keywords

shape memory alloy / single crystal / temperature gradient

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