Oxidation Behavior of NiTi-Al Based Alloy with Nb and Mo Additions

3rd Annual International Workshop on Materials Science and Engineering

Song, Xiaoyun^1 ; Ye, Wenjun^1 ; Hui, Songxiao^1 ; Li, Yan^2

State Key Laboratory of Nonferrous Metals and Processes, General Research Institute for Nonferrous Metals, Beijing

100088, China^1

School of Materials Science and Engineering, Beihang University, Beijing

100191, China^2

关键词: Al-based alloys;    Cyclic oxidation tests;    Doping effects;    Mo additions;    Multilayer structures;    Ni-45Ti-5Al alloys;    Oxidation behaviors;    Solid solution phasis;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/250/1/012005/pdf
DOI  :  10.1088/1757-899X/250/1/012005

来源: IOP

【 摘 要 】

Oxidation behavior of a Ni-45Ti-5Al-2Nb-1Mo (composition in at %) alloy was studied in comparison with the Ni-45Ti-5Al alloy by X-ray diffraction (XRD), scanning electron microscopy (SEM) and cyclic oxidation tests. The results show that the microstructure of Ni-45Ti-5Al-2Nb-1Mo alloy is composed of NiTi matrix, Ti2Ni and (Nb, Ti) solid solution phases. By 2 at% Nb and 1 at% Mo addition, the Ni-45Ti-5Al-2Nb-1Mo alloy shows excellent oxidation resistance. The mass gain of Ni-45Ti-5Al-2Nb-1Mo alloy after 100 h exposure at 800 °C is 2.29 mg/cm2, which is much lower than that of Ni-45Ti-5Al alloy. This is mainly resulted from the doping effect of Nb and Mo in TiO2and the formation of a continuous Al2O3layer by Nb and Mo addition. The oxide scale of the present alloy is with multi-layer structure in order of TiO2 layer/ Al2O3 + NiAl2O4 mixture layer/ TiO2 layer/ Nb-rich TiO2 layer/ Ni3Ti layer from outside.