First Cycle Effect of Polycrystalline CuZnAl Shape Memory Alloy during Thermal-Mechanical Cycling

Wenge LIU+;Min ZHU;Dazhi YANG, Dept. of Materials Engineering, Dalian University of Technology, Dalian, 116024, ChinaZhongguang WANG, State Key Laboratory for Fatigue and Fracture of Materials, Institute of Metal Research, Academia Sinica, Shenyang, 110015, China

摘 要：<正> The thermal-mechanical （T-M） cycles at constant strain of a polycrystalline CuZnAl alloy have beenstudied in the. present work. In-situ optical microscopic observations have been made to reveal thefeatures of the phase transitions during T-M cycling. The variation of stress-temperature （S-T）curves and electrical resistance-temperature （R-T） curves accompanying with T-M cycling havebeen measured by tensile test and electrical resistance measurements. It has been found that thepolycrystalline CuZnAl alloy shows apparent morphology changes and properties variations in thefirst cycle during T-M cycling which is called the first cycle effect in the present work. The stabletransformation procedure in the T-M cycle is: martensiteparent phase +residual acicularmartensite. This residual martensite possesses the character of stress-induced martensite.

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