一种修正的应变范围区分法

针对高强度、低延性材料非弹性应变范围小、难以区分的特点,提出一种修正的应变范围区分方法。该方法不区分非弹性应变中的塑性和蠕变,定义了3种基本类型的非弹性应变范围,即拉伸塑性-压缩塑性非弹性应变范围、拉伸塑性和蠕变-压缩塑性非弹性应变范围和拉伸塑性-压缩塑性和蠕变非弹性应变范围。对同时包含拉/压蠕变的循环,采用线性累积损伤法则预测其寿命。用Rene’95材料650℃下控制应变的循环松弛试验数据对修正方法进行了验证,结果表明:对Rene’95材料的蠕变疲劳寿命,修正方法的预测能力好于应变范围区分法(SRP),对基本试验的寿命预测精度基本上在2倍范围之内。 

Modified Strain range Partitioning Method

According to the character that for the high strength,low ductility alloys,the inelastic strains is small and difficult to determine,a modified method of Strain Range Partitioning (SRP) was presented.Plasticity and creep are not partitioned,and three basic kinds of inelastic strain ranges are defined in the modified SRP as follows:tensile plasticity-compressive plasticity was designated as pp inelastic strain range,tensile plasticity and creep-compressive plasticity was designated as cp inelastic strain range and tensile plasticity-compressive plasticity and creep was designated as pc inelastic strain range.The linear damage rule was applied to predict the life of cc type cycle that contains both tensile creep and compressive creep.The modified SRP was evaluated for its ability to predict creep-fatigue behavior of thermomechanically processed advanced nickel-base superalloy used for turbine disks,Rene’95,at 650℃.The result indicates that the predictive ability of the modified SRP is better than SRP, and the prediction of the is mostly within a scatter band of 2 compared to the baseline test data.