Cu-Al-Mn-Zn-Zr记忆合金的应力诱发马氏体相变及其逆转变

STRESS-INDUCED MARTENSITE TRANSFORMATION AND ITS REVERSIBILITY IN Cu-18.4Al-8.7Mn-3.4Zn-0.1Zr Alloy

利用拉伸实验、电阻-温度曲线测量、X射线衍射、金相与透射电镜观察等方法研究了Cu-18.4Al-8.7Mn-3.4Zn-0.1Zr(原子分数,％)合金应力诱发马氏体的稳定性与可逆性.结果表明:在Ms以上变形,实验合金发生应力诱发β1→M18R转变,但应力诱发马氏体转变很难进行完全,当变形量高达7.5％时,仍存在未发生应力诱发转变的母相.应力诱发马氏体的稳定性和可逆性与变形量大小有关,合金经大变形量变形后,即使在250℃油浴中回复,仍存在未发生逆变的应力诱发马氏体.在一定的变形条件下,经适量变形的应力诱发马氏体具有很高的可逆性和稳定性,实验合金在Ms以上10—50℃温度范围内变形6.5％-9.0％时,相变滞后宽度可达90℃以上,记忆应变>3.5％.

The stress-induced martensite transformation and its reversibility in Cu-18.4Al-8.7Mn-3.4Zn-0.lZr(atomic fraction, %) alloy have been studied by means of tensile test, resistance-temperature curve measurement, X-ray diffraction, optical metalloscope and TEM observation. It is shown that the transformation mechanism in the tested alloy is stress-induced β1 →M18R transformation. When the tensile strain is up to 7.5%, there is a little parent phase untransformed into the martensite. There exists stress-induced martensite non-reversible transformed, when it recovers in the 250 ℃ oil bath for 40s. Under the appropriate deformation condition, the stress-induced martensite subjecting to suitable tensile strain has both high stability and good reversibility. The tested alloy is deformed at temperature between Ms+10 ℃ and Ms+50 ℃ and on the strain between 6.5% and 9.0%, its transformation hysteresis and shape memory strain are higher than 90 ℃ and 3.5% respectively.