超声拉伸纳米复相陶瓷非局部力学试验研究

Experimental Research on Nonlocal Mechanical Behaviorsof Micro-nanocomposited Ceramics under Ultrasonic Tensile Test

提出了纳米复相陶瓷在超声振动条件下的单向拉伸实验方法,通过对超声振动拉伸下材料特性的实验研究,基于非局部理论,研究纳米复相陶瓷材料的断裂机制、微观组织和力学性能,获得超声频率对轴向拉伸应力的影响规律及非局部衰减率的变化规律。试验结果表明,试件在给定超声振动频率范围内拉伸时应力出现衰减现象,且随频率的增大更明显,对拉伸断口进行微观分析,结果表明,超声振动改变了材料的断裂方式和微观组织结构,增强了材料的韧性,说明在超声激励下更容易实现延性域加工。试验结果与非局部理论分析一致。

The uniaxial tensile test method of micronanocomposited ceramics is put forward under ultrasonic excitation. Based on nonlocal theory, fracture mechanism,microstructure and mechanical properties of micronanoeom posited ceramics are studied through the experimental study of material properties under ultrasonic vibration tensile test,and the effects of ultrasonic frequency on the axial tensile stress and nonlocal decay rate are obtained. The results of experiments show that tensile stress is attenuated when the tensile of the specimen is in the ultrasonic vibra tion frequency ranges and this attenuation phenomenon becomes more and more evident by the increase of the ultra sonic frequencies. Microscopical analysis of tensile fracture is conducted. It shows that ultrasonic vibration changes the fraeture mode and mierostructure and improves the toughness of the material,and it says that it is much easier to achieve ductilemode machining under ultrasonic excitation. The results of experiments are in accordance with the analysis of nonlocal theory.