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采用场发射扫描电子显微镜、透射电子显微镜、X射线衍射和差示扫描量热法,并在NaCl溶液中进行电化学和浸渍试验,研究添加不同含量的Mn或Ti(0.4%,0.7%,和1.0%,质量分数)对Cu-Al-Ni形状记忆合金的显微组织、形状记忆效应和腐蚀行为的影响。研究结果表明,显微组织、形状记忆效应和腐蚀特征对成分变化高度敏感。当添加0.7%Mn或0.7%Ti时,合金出现了最高的应变回复率。这可能是由于存在晶粒细化和高体积分数沉淀。电化学测试表明,在Cu-Al-Ni-Mn和Cu-Al-Ni-Ti形状记忆合金中氧化层的形成提供了良好的钝化保护,从而提高了合金的耐蚀性。浸渍试验表明,在Cu-Al-Ni-Mn形状记忆合金中,氧化层发生了点状腐蚀。腐蚀坑附近的腐蚀产物富Al/Mn氧化物而贫铜,而在腐蚀坑内腐蚀产物富铜。在Cu-Al-Ni-Ti形状记忆合金样品表面发生了局部腐蚀,而在基体中发生了脱铝腐蚀。
Field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction and differential scanning calorimetry were used to investigate the effects of adding different amounts of Mn or Ti (0.4%, 0.7%, and 1.0%, mass fraction) on the microstructure, shape memory effect and corrosion behavior of Cu-Al-Ni shape memory alloy. The results show that the microstructure, shape memory effect and corrosion characteristics are highly sensitive to compositional changes. When adding 0.7% Mn or 0.7% Ti, the highest strain recovery appeared. This may be due to the existence of grain refinement and high volume fraction precipitation. Electrochemical tests showed that the formation of oxide layer in Cu-Al-Ni-Mn and Cu-Al-Ni-Ti shape memory alloys provided good passivation protection and improved the corrosion resistance of the alloy. The impregnation test showed that the oxide layer occurred pitting corrosion in the Cu-Al-Ni-Mn shape memory alloy. The corrosion products near the corrosion pits are rich in Al / Mn oxides and are poor in copper, while the corrosion products in the corrosion pits are rich in copper. Local corrosion occurred on the surface of Cu-Al-Ni-Ti shape memory alloy samples, and dealumination occurred in the matrix.