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    GH3536高温合金的高温蠕变疲劳寿命预测

    High Temperature Creep Fatigue Life Prediction of GH3536 Superalloy

    • 摘要: 在600,800,900,1 000 ℃对火焰筒材料GH3536高温合金进行了应变控制的蠕变疲劳试验,研究了该合金的高温蠕变疲劳行为;利用考虑温度和保载影响的Coffin-Manson蠕变疲劳寿命预测模型对其蠕变疲劳寿命进行预测,并与试验结果进行对比。结果表明:GH3536合金在600~900 ℃表现出不同程度的循环硬化现象,随着温度的升高,硬化程度减弱;1 000 ℃下在初始循环阶段出现轻微软化现象,随后峰值应力保持稳定直至合金失效。在800~1 000 ℃下的蠕变疲劳半寿命保载阶段,GH3536合金表现出显著的应力松弛现象。随着温度的升高,合金的蠕变疲劳寿命缩短;在600 ℃下最大应变保载过程对疲劳寿命基本没有影响,而在800~1 000 ℃下会显著缩短蠕变疲劳寿命。考虑温度和保载效应的疲劳寿命预测模型预测得到的不同温度下的蠕变疲劳寿命大部分位于2倍分散带内,该模型可以较准确地预测GH3536合金的蠕变疲劳寿命。

       

      Abstract: Strain-controlled creep fatigue tests were conducted on GH3536 superalloy for combustion liner materials at 600, 800, 900, 1 000 ℃, and the high temperature creep fatigue behavior of the alloy was studied. The Coffin-Manson equation considering the influence of temperature and load holding was developed. The creep fatigue life was predicted by the model, and was compared with the test results. The results show that GH3536 alloy exhibited varying degrees of cyclic hardening between 600 ℃ and 900 ℃, and the hardening degree decreased with increasing temperature. At 1 000 ℃, slight cyclic softening occurred during initial cycles, and then the peak stress remained stable until the alloy failed. During the creep fatigue half-life load holding stage at 800–1 000 ℃, GH3536 alloy showed a significant stress relaxation phenomenon. With the increase of temperature, the creep fatigue life of the alloy decreased. The maximum strain holding stage had basically no effect on fatigue life at 600 ℃, and resulted in the obviouse decrease of creep fatigue life at temperatures ranging from 800 ℃ to 1 000 ℃. The creep fatigue life predicted by the fatigue life prediction model considering temperature and load holding effect at different temperatures was mostly within the double scatter band. This model could accurately predict the creep fatigue life of GH3536 alloy.

       

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