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在 ９５０℃ｔ对［０ ０１］、［０１２］、［１１２］、［０１１］和［１１４４］晶体取向的镍基单晶超合金 ＤＤ３试样进行了对称循环低周疲劳（ＩＣＦ）试验．应变率取１．０×１０~（－２），１．３３×１０~（－３），０．３３×１０~（－３）ｓ~（－１）．试验结果表明，ＬＣＦ特性显著地取决于晶体取向和应变率．试样断口细观分析表明，除了［０ ０ １］取向试样外，其余所有试样断口上均有明显的等间距疲劳纹．这些疲劳纹由微裂纹组成，其间距取决于试样的晶体取向和总应变范围．基于晶体滑移理论，建立了疲劳纹间距和总分切应变范围及取向和应变率函数的一个简单关系．对Ｌａｌｌ－Ｃｈｉｎ－Ｐｏｐｅ（ＬＣＰ）模型进行修正并推广应用于循环塑性和疲劳寿命研究，提出了一个晶体取向和应变率参数，该参数可以很好地描述镍基单晶超合金高温低周疲劳循环塑性和疲劳寿命的晶体取向和应变率相关性．
Symmetric Cyclic Low Cycle Fatigue (ICF) tests were performed on the Ni-based single crystal superalloy DD3 samples of [001], [012], [112], [011] and [1144] crystal orientation at 950 ° C. The strain rate was 1.0 × 10 -2, 1.33 × 10 -3 and 0.33 × 10 -3 s -1. The experimental results show that LCF properties depend significantly on the crystal orientation and strain rate. The microscopic analysis of the fracture surface of the specimen showed that all the specimens except the [0 0 1] oriented specimen had obvious equal-pitch fatigue marks on the fracture surface. These fatigue patterns consist of microcracks whose spacing depends on the crystal orientation and the total strain range of the specimen. Based on the theory of crystal slip, a simple relationship between fatigue crack spacing and total shear strain range and orientation and strain rate functions is established. The Lall-Chin-Pope (LCP) model is modified and extended to the research of cyclic plasticity and fatigue life. A crystal orientation and strain rate parameter is proposed, which can well describe the high temperature and low cycle fatigue of nickel base single crystal superalloy Correlation between Crystallographic Orientation and Strain Rate of Cyclic Plasticity and Fatigue Life.