保载条件下FGH95材料的疲劳特性及寿命建模

Fatigue characteristics of FGH95PM superalloy under dwell condition and modeling for life prediction

针对FGH95粉末冶金材料进行了650℃时不同保载形式（拉伸保载、压缩保载和拉压保载）的疲劳试验，分析了其变形特征和疲劳寿命分布特征以及保载对疲劳寿命的影响．并据此，为改进保载条件下疲劳寿命的建模，提出了迟滞环位置一形状修正因子的概念，进而得到了一种修正的非弹性应变能～寿命方程．经对该材料疲劳试验寿命的建模和计算分析表明：该方法相比其他几种工程上经常采用的寿命预测方程，较好地解决粉末冶金材料高温保载疲劳时的寿命建模问题，且该方程对试验寿命预测的精度更高，形式简单，具有明显的物理意义．

This paper performs describes under different dwell conditions of FGH95 powder metallurgy superalloy at 650℃ ,and analyses its features of deformation and life distribution, and studies the obvious effect on life due to dwell. Then for improving the life modeling under dwell conditions,a modified factor of position-shape of hysteresis loop is presented,and a modified life equation as function of inelastic energy is established. Comparing with the predictive results of other life equations, the modified life equation has higher predictive precision, more compact form and clearer physical meaning. So life prediction of PM FGH95 under dwell conditions can be solved better.