Twice reverse shape memory effect in CuZnAl shape memory alloy①
(1. School of Materials Science and Engineering, Central South University,
Changsha 410083, China;
2. School of Materials Science and Engineering, Hefei University of Technology,
Hefei 230009, China)
Changsha 410083, China;
2. School of Materials Science and Engineering, Hefei University of Technology,
Hefei 230009, China)
Abstract: The variations of the shape memory effects in the Cu-13Zn-15Al(mole fraction, %) alloy upon successive heating (the rate of heating is 5℃/min) have been studied by means ofρ—Tcurve , shape memory effect measurement, optical metallographical observation and X-ray diffraction. The first abnormal reverse shape memory effect occurs when the tested alloy is heated to the temperature below 320℃; when it is heated to the temperature between 320℃and 450℃, the forward shape memory effect occurs; in the two stages, the shape of the sample remains the same as that in the furnace when it is taken out from the furnace and air-cooled; when the tested alloy is heated to the temperature above 450℃, the shape of the sample remains unchanged during heating, but the second reverse shape memory effect occurs after it is air-quenched.
Key words: CuZnAl alloy; shape memory alloy; martensite; reverse shape memory effect