摘要
金属间化合物Ni_3Al在其熔点(1390℃)以下具长程有序结构,屈服强度随温度升高而增大,很有可能成为新型的高温结构材料。 1979年发现Ni_3Al中加入微量硼可使室温塑性显著提高。近年证实加Zr可进一步改善室温和高温强度,加Cr能减轻或消除动态脆性。高温材料除了需要良好的力学性能外,必须具有优异的抗高温氧化性能。但关于Cr和/或Zr对抗氧化性能的影响,尚未见系统报导。本工作研究Zr和Cr对Ni_3Al合金850～1150℃氧化增重的影响,探讨Ni_3Al合金氧化过程中Cr和Zr的作用。
The isothermal oxidation behaviour of Ni_3Al-0.lB alloy containing Zr or Cr additions has been studied over a temperature range of 850-1150℃ and for periods up to 100 h. The structure of scale and phase transformation of the surface zone beneath the scale have been investigated by X-ray diffraction, scanning electron microscopy and electron microprobe analyzer ete. The results show that isothermal oxidation kinetics of the alloys at variour temperatures all obey the parabolic law. The additions of Zr, Cr or Cr + Zr obviously improye oxidation resistance at 850 to 950℃ and worsen it at 1050 to 1150℃. The addition of Zr leads to the formation of adherent scale at all temperatures, since the internal oxides are developed like 'tree roots'' between the oxide scale and the substrate. But, Zr clearly increases the diffusion of oxygen along A1_2O_3 grain boundaries at elevated temperature. The oxidation scale is generally made of NiO, NiAl_2O_4 and A1_2O_2, There is a little Cr_2O_3 in Cr containing alloy.
出处
《中国腐蚀与防护学报》
CAS
CSCD
1990年第2期171-176,共6页
Journal of Chinese Society For Corrosion and Protection
基金
中科院腐蚀科学开放实验室资助
