( 1. 北京有色金属研究总院 能源材料与技术研究中心, 北京 100088;
2. 天津理工大学 材料科学与工程学院, 天津 300191;
3. 河北工业大学 材料科学与工程学院, 天津 300132)
摘 要: 通过恰当的成分设计， 获得了具有较低马氏体相变温度及较宽相变滞后的Cu-Al-Mn-Nb形状记忆合金。 用差热分析法(DSC)测得Cu-26.8Al-4.8Mn-1.0Nb(摩尔分数， %)合金在降温时马氏体相变最激烈的温度为-32 ℃； 升温时奥氏体相变最激烈时的温度为68 ℃； 相变滞后宽度达100 ℃。 透射电镜、 扫描电镜及X射线衍射分析表明， 该合金的马氏体为2H型结构， 宽滞后效应是由于合金进行马氏体相变时析出了点状富铌颗粒从而松驰掉一部分弹性应变能而产生的。 该合金在表面应变为4%时， 弯曲变形试样的形状回复率达93%以上， 在室温下时效2个月后， 其形状回复率没有发生明显恶化。 室温下其抗拉强度约为550 MPa， 屈服强度约为380 MPa， 塑性延伸率约为7%。
关键字: Cu-Al-Mn-Nb； 形状记忆合金； 相变滞后； 记忆效应； 力学性能
（ 1. Research Center of Energy Materials and Technology,
Beijing General Research Institute for Nonferrous Metals, Beijing 10088, China;
2. School of Materials Science and Engineering,
Tianjin University of Technology,Tianjin 300191, China;
3. School of Materials Science and Engineering,
Hebei University of Technology,Tianjin 300132, China）
Abstract: Cu-Al-Mn-Nb shape memory alloy with broad hysteresis and low martensitic transformation temperature can be obtained by properly designing on its composition. Differential scanning calorimetry (DSC) analyses show that the t*M of the alloy is about -32 ℃, t*A is about 68 ℃, and the hysteresis range is about 100 ℃. Transmitted electronic microscopy (TEM), scanning electronic microscopy (SEM) and X-ray diffractrometry (XRD) analyses indicate that the martensite in the alloy is characterized by 2H-type texture, and its broad hysteresis effect is likely a result of Nb-rich grains separated out during the martensitic transformation, which would have relaxed some elastic strain energy. The alloy has favorable mechanical properties and shape memory effect, with tensile strength of about 250 MPa, the yield stress of about 380 MPa, the plastic elongation of about 7%, and the shape recovery rate over 93% after bending deformation at surface strain of 4%. Aging at room temperature for 2 months the shape recovery rate of the alloy has not evidently deteriorated.
Key words: Cu-Al-Mn-Nb; shape memory alloy; phase transformation hysteresis; shape memory effect; mechanical properties
