Microstructure and High-Temperature Oxidation Behavior of Dy-Doped Nb-Si-Based Alloys

• 来源期刊: 金属学报（英文版）
• 年，卷（期）: 2018,（7）
• 页码范围: 742-752
• 页数: 11页
• 语种: 英文

摘要

Microstructures and oxidation behaviors of four Dy-doped Nb-Si-based alloys at 1250 ℃ were investigated.The nominal compositions of the four alloys are Nb-15Si-24Ti-4Cr-2Al-2Hf-xDy (at.％),where x =0,0.05,0.10 and 0.15,respectively.Results showed that the four alloys all consisted of Nbss,αNbsSi3 and γNbsSi3,and the addition of Dy produced no obvious effect on the phase constitution and the microstructures of Nb-Si-based alloys.After oxidation at 1250 ℃C for 58 h,it was found that the addition of Dy accelerated the oxidation rate of Nb-Si-based alloys and caused a larger weight gain,accompanied by the formation of a more porous and less protective oxide scale.The oxides of Nb2O5,Ti2Nb10O29,TiNb2O7,Ti0.4Cr0.3Nb0.3O2 and glassy SiO2 were formed on Dy-doped Nb-Si-based alloys.The high-temperature oxidation mechanism of Dy-doped Nb-Si-based alloys was discussed.