High-Temperature Oxidation Resistance of Ti-45Al-8(Nb,Hf,Y)-0.2B Alloys

作者：Wang Yanjing^*; Li Fei; Gu Yanpeng; Wang Jijie; Du Xinghao

来源：Rare Metal Materials and Engineering, 2016, 45(1): 132-136.

• TiAl intermetallic compound
• high temperature oxidation
• Hf, Y microalloying

Three kinds of alloys were designed by making the niobium equivalent of 8at% approximately, and the compositions of the alloys were Ti-45Al-8Nb-0.2B, Ti-45Al-7Nb-0.1Hf-0.1Y-0.2B as well as Ti-45Al-4Nb-0.5Hf-0.1Y-0.2B (at%). The interrupted oxidation behaviors of alloys at 900 degrees C in static air were studied. The results show that combined addition of Hf and Y can enhance adherence between the oxide film and the substrate; Ti-45Al-4Nb-0.5Hf-0.1Y-0.2B alloy with the low Nb/Hf ratio has a lower oxidation gain and strong oxidation resistance. Ti-45Al-7Nb-0.1Hf-0.1Y-0.2B alloy with the high Nb/Hf ratio has a higher oxidation gain and poor oxidation resistance. Oxidized samples were examined by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction analysis (XRD). It is found that combined addition of Hf and Y can promote the whisker growth of Al2O3 oxide scale, which improves adherence of the oxide film; a large number of continuous and compact Al2O3 oxide scale has been found in the alloys with low Nb/Hf ratio, which improves oxidation resistance of the alloy; external oxidation in the alloy with high Nb/Hf ratio results in higher oxidation gain and poor oxidation resistance.

• 出版日期2016-1
• 单位沈阳航空航天大学