Grain boundary engineering for control of fatigue fracture and improvement of fatigue property in electrodeposited nanocrystalline materials

为了系统地阐明纳米晶金属材料的疲劳性能和疲劳断裂机理，对电沉积法制备的纳米晶镍、镍基合金和铁基合金的疲劳性能和断裂与循环应力作用下的微观组织变化进行了实验研究，结果表明，这些纳米晶材料的疲劳极限比传统晶粒结构的多晶材料提高了约2倍。定量评价了循环应力作用下的晶粒度、织构和晶界组织的变化。结果表明，疲劳性能和断裂过程是由这些微观组织变化决定的。

The fatigue property and fracture in nanocrystalline nickel, nickel based alloy and iron based alloy which produced by electrodeposition was experimentally investigated in relation to microstructural change by cyclic stress, to systematically clarify the fatigue property and fatigue fracture mechanism in nanocrystalline metallic materials.As a result, these nanocrystalline materials show about 2 times higher fatigue limit than polycrystalline materials with conventional grain structure. The changes in grain size, texture and grain boundary microstructure by cyclic stress were quantitatively evaluated. It was concluded that the fatigue property and fracture process was dominated by these microstructural changes.