GH33A合金热机械疲劳寿命曲线讨论

DISCUSSION ON CURVE OF THERMAL MECHANICAL LIFE OF ALLOY GH33A

通过比较ＧＨ３３Ａ合金热机械疲劳寿命的三种不同描述方法，即Δεｍ～Ｎｆ、Δεｔ～Ｎｆ和Δεｉｎ～Ｎｆ寿命曲线，讨论了不同描述方法时相位差对疲劳寿命的影响，并从实验室模拟热机械疲劳试验方法和材料及其构件实际工况的角度对此加以分析。提出无论是在模拟试验中，还是对疲劳寿命的描述均应采用总应变范围Δεｔ或非弹性应变范围Δεｉｎ，才符合近工况模拟试验和疲劳寿命预测的基本条件。

In this paper, the influence of phase difference on thermal mechanical fatigue life is discussed by comparing with three different kinds of life curves which are expressed in terms of mechanical stain range Δε m￣N f, total strain range Δε t￣N f and inelastical strain range Δε in ￣N f. These curves are analyzed from the test of the laboratory simulating thermal mechanical fatigue and the actual service conditions of engineering materials as well as their components. The results indicated that the terms of total strain range Δε t or inelastic strain range Δε in must be used not only in tests but also in expressing life curve of thermal mechanical fatigue. Only in this way, it will meet the basic conditions of simulating tests and predicating fatigue life.