300M钢拉伸性能计算及疲劳性能预测

发布时间：2018-03-16 07:45

本文选题：EET　切入点：300M　出处：《辽宁工程技术大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文应用“固体与分子经验电子理论”(EET)计算研究了300M钢的不同微观组织特征相的电子结构参数统计值,并计算了低温回火状态下300M钢的力学性能,计算结果与实验值符合较好。计算研究了不同回火组织特征相界面电子结构参数的最大值Δρmax、最小值Δρmin,研究发现最大值Δρmax、最小值Δρmin分别与相界面的最大、最小特征强度σ*max和σ*min相对应,原子状态组数σ与界面稳定性相对应；研究结果表明：300M钢中温回火屈氏体组织的σ*min较大,可有效阻止裂纹的萌生,因此疲劳裂纹的孕育期N0较长；同时,中温回火屈氏体组织的σ*max较大,裂纹在界面处扩展受阻,裂纹的扩展门槛值△Kth较大；原子状态组数σ较大,循环载荷作用下界面的稳定性愈不容易遭到破坏,界面越稳定,因此循环周数N较高。中温回火屈氏体组织中N0、ΔKth、N均出现峰值,因此疲劳性能最好。
[Abstract]:In this paper, the statistical values of electronic structure parameters of different microstructure characteristic phases of 300M steel have been calculated by using "solid and Molecular empirical Electron Theory", and the mechanical properties of 300M steel under low-tempering condition have been calculated. The calculated results are in good agreement with the experimental data. The maximum 螖蟻 maxand the minimum 螖蟻 min of the electronic structure parameters of different tempering microstructure characteristic phase interfaces are calculated and studied. It is found that the maximum 螖蟻 maxand the minimum 螖蟻 min are the maximum of the phase interface, respectively. The minimum characteristic strength 蟽 _ (max) corresponds to 蟽 _ (min), and the number of atomic state groups 蟽 _ (a) corresponds to the interfacial stability. The results show that 蟽 _ (min) of tempering and tempering at middle temperature is larger, which can effectively prevent the initiation of crack, so the incubation period of fatigue crack is longer. At the same time, the 蟽 max of the tempering body is larger, the crack propagation is blocked at the interface, the Kth of the crack growth threshold is larger, the number of atomic states 蟽 is larger, and the stability of the interface is less easily destroyed under cyclic loading. The more stable the interface, the higher the cycle number N and the peak value of N _ 0 and 螖 K _ (thn) in the tempering medium temperature, so the fatigue performance is the best.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG142.1

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