Y元素对Cu-Al-Ni高温形状记忆合金性能的影响

Effect of Y Element on the Properties of Cu-Al-Ni High Temperature Shape Memory Alloy

利用XRD、OM、SEM、TEM、电子万能力学试验机以及电化学工作站对Cu-13Al-4Ni-xY(x=0.2、0.5,质量分数,%)高温形状记忆合金进行组织观察和性能测试。研究结果表明,加入Y元素后,Cu-13Al-4Ni-xY合金的室温组织主要为18R马氏体基体,以及具有六方结构的(Cu,Al,Ni)_(4)Y第二相。随着Y元素含量的提高,Cu-13Al-4Ni-xY合金的力学性能大幅提升。当Y含量为0.5%时,压缩断裂应变与断裂强度从未添加Y时的10.5%和580 MPa分别提升到了19.3%和1185 MPa,且合金的断裂形式由沿晶断裂变为穿晶断裂。电化学实验结果表明,Y元素的添加使合金耐蚀性稍有下降。

Cu-Al-Ni alloys are not yet widely used due to issues related to their coarse grains,unacceptable plasticity,and poor thermal stability.Here,the physical and mechanical properties,as well as the corrosion behavior,of Cu-Al-Ni alloys doped with Y element(Cu-13Al-4Ni-xY(x=0.2,0.5,mass fraction,%))were studied.XRD,OM,SEM,TEM,electronic universal testing machine,and electrochemical workstation were used to characterize the microstructures and measure the properties of the Cu-13Al-4Ni-xY alloys.The results showed that at room temperature,the microstructure of Cu-13Al-4Ni-xY alloys was mainly an 18R martensite matrix.The(Cu,Al,Ni)4Y second phase was characterized to have a hexagonal structure.The mechanical properties of the Cu-13Al-4Ni-xY alloys improved as the Y element content increased.For example,when the Y content was increased from 0%to 0.5%,the compressive fracture strain increased from 10.5%to 19.3%and the fracture strength increased from 580 to 1185 MPa.Additionally,the fracture type of the alloy changed from intergranular to transgranular with the addition of Y.Finally,the results from electrochemical experiments showed that the corrosion behavior of the alloys decreased slightly with the addition of Y.