Twice reverse shape memory effect in CuZnAl shape memory alloy

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 st udied by means of ρ—T curve,shape memory effect measurement,optical met allographical observation and X-ray diffraction. The first abnormal reverse sha pe 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 r emains 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.