( 1. 北京有色金屬研究總院 能源材料與技術(shù)研究中心, 北京 100088;
2. 天津理工大學(xué) 材料科學(xué)與工程學(xué)院, 天津 300191;
3. 河北工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院, 天津 300132)
摘 要: 通過恰當?shù)某煞衷O(shè)計， 獲得了具有較低馬氏體相變溫度及較寬相變滯后的Cu-Al-Mn-Nb形狀記憶合金。 用差熱分析法(DSC)測得Cu-26.8Al-4.8Mn-1.0Nb(摩爾分數(shù)， %)合金在降溫時馬氏體相變最激烈的溫度為-32 ℃； 升溫時奧氏體相變最激烈時的溫度為68 ℃； 相變滯后寬度達100 ℃。 透射電鏡、 掃描電鏡及X射線衍射分析表明， 該合金的馬氏體為2H型結(jié)構(gòu)， 寬滯后效應(yīng)是由于合金進行馬氏體相變時析出了點狀富鈮顆粒從而松馳掉一部分彈性應(yīng)變能而產(chǎn)生的。 該合金在表面應(yīng)變?yōu)?%時， 彎曲變形試樣的形狀回復(fù)率達93%以上， 在室溫下時效2個月后， 其形狀回復(fù)率沒有發(fā)生明顯惡化。 室溫下其抗拉強度約為550 MPa， 屈服強度約為380 MPa， 塑性延伸率約為7%。
關(guān)鍵字: Cu-Al-Mn-Nb； 形狀記憶合金； 相變滯后； 記憶效應(yīng)； 力學(xué)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
