SINGLE CRYSTAL GROWTH OF Cu BASED SHAPE MEMORY ALLOY AND ITS THERMODYNAMIC ANALYSIS
Tan Shusong(Department of Material Science and Engineering, Central South University of Technology, Changsha, 410083, China)Xu Huibin(Beijing Aviation and Aeronautic University, Beijing, China )Ngal Leo; Tangwai(City Polytechnic of Hong Kong Material Rese
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 relation ship between the possible maximum growth rate of the single crystal and the temperature gradient at the liquid-solid interface. Maximum growth rate is 5mm/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.