高温钛合金中杂质元素Fe的扩散行为及其对蠕变抗力的损害作用

高温钛合金是先进航空发动机压气机应用的理想材料,代替钢或镍基高温合金,可以显著提高发动机的推重比和服役性能.随着钛合金使用温度的提高,高温蠕变抗力越来越成为影响其使用温度和使用寿命最关键的力学性能.在400～600℃的温度范围内,钛合金的蠕变变形一般受位错攀移机制所控制,蠕变激活能近似等于有效扩散激活能,因此,扩散是影响钛合金高温蠕变抗力的最主要因素.杂质元素Fe在钛合金中具有反常大的扩散能力,是Ti自扩散系数的103～105倍,在Ti中的扩散可能受离解扩散机制所控制.钛合金中的微量Fe同时会显著促进Ti的自扩散,提高位错攀移速率,从而降低蠕变抗力.为了改善高温钛合金的蠕变性能,需要严格控制原材料如海绵钛和中间合金中杂质Fe的含量.

Diffusion Behavior of Impurity Iron in High Temperature Titanium Alloys and Its Detrimental Effect on Creep Resistance

High temperature titanium alloys were idea materials for advanced aero-engine compressor use due to their excellent contribution to the spectacular progress in thrust-to-mass ratio and operating performances,which had been achieved through the substitution of titanium alloys for steel or Ni-based superalloys.With increasing the operating temperature of titanium alloys,creep resistance becomes the most important mechanical property which may affect the operating temperature and service lifetime.Over the temp...