中低温退火处理工艺下Ti40合金高温蠕变机制的研究(Ⅰ)——蠕变本构关系

Creep Mechanism of Ti40 Alloy after Annealing Treatment at Moderate or Low Temperature(Ⅰ)——Constitutive Equation

对Ti40合金环材进行600℃,4h退火处理,并测试合金在500～550℃温度范围不同应力下蠕变性能。结果表明,Ti40合金在500～550℃的温度范围的蠕变行为应该分为两个区间,区间Ⅰ为500～520℃温度范围;区间Ⅱ为535～550℃温度范围,在两个温度区间内蠕变本构方程不同。分析认为,在低温区(500～520℃)应力对位错的滑移影响较大,热激活控制的位错攀移控制稳态蠕变变形;当温度升高时,扩散对蠕变变形的贡献越来越大,在高温区(535～550℃),合金的蠕变可能受自扩散或合金元素的扩散控制。

The creep experiment of Ti40 alloy after annealing treatment at 600 ℃ for 4 h was carried on in a temperature range from 500 ℃ to 550 ℃ with various stresses. The experimental results indicate that the creep behavior can be analyzed in two temperature intervals in this creep temperature range. The first temperature interval is ranging from 500 ℃ to 520 ℃; the second one is ranging from 535 ℃ to 550 ℃. In different temperature intervals, the alloy has different creep constitutive equations. Judging by the analysis, it is deduced that the stress has obvious effect on dislocations glide and climbing controlled by heat activation when the temperature interval was at lower temperatures （500-520 ℃）. With increasing temperature, the diffusion has more and more effect on the creep deformation. In higher temperature range （535-550 ℃）, the creep deformation may be determined by self-diffuslon or alloying element diffusion.