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采用晶体取向不同的99.999％Al单晶试样,进行拉压对称的应变控制疲劳试验。应变幅为2×10~(-3)。记录了各循环周次的应力、应力-应变滞后回线,根据回线的面积和形状计算了循环形变中的能量损耗、摩擦应力、反馈应力及形状参量。观察了滑移形貌,发现晶体取向对上述各量均有很大影响。多滑移取向晶体比单滑移取向晶体具有大得多的初始硬化率、饱和应力值和能量损耗。而滞后回线的形状则后者较接近矩形,其形状参量V_H比前者大,探讨了各参量间的关系及它们与材料内部位错结构的联系。
A strain-controlled fatigue test of tension-compression symmetry was carried out using 99.999% Al single crystal samples with different crystal orientations. Strain amplitude is 2 × 10 ~ (-3). The stresses and stress-strain hysteresis loops of each cycle were recorded. The energy loss, friction stress, feedback stress and shape parameters in cyclic deformation were calculated according to the area and shape of the loop. The slip morphology was observed and the crystal orientation was found to have a significant effect on each of these quantities. Multi-slip oriented crystals have much larger initial stiffness, saturation stress values, and energy losses than single-slip oriented crystals. However, the shape of the hysteresis loop is closer to the rectangle, and the shape parameter V_H is larger than the former, and the relationship between the parameters and the relationship between them and the dislocation structure inside the material are discussed.