磨料水射流冲蚀金属损伤形貌特征及机理研究

针对前混合磨料水射流冲蚀过程,进行了冲蚀试验及仿真研究.从试验中得到了材料冲蚀损伤形貌特征.采用SPH耦合FEM方法建立相应的冲蚀模型,对材料冲蚀过程进行模拟分析,揭示了材料损伤形貌特征产生的机理.结果表明:随着冲蚀深度的增加,磨料颗粒的冲蚀动能逐渐减小,冲蚀角度逐渐增大,材料冲蚀损伤由微切削和微犁削逐渐变为冲击变形,材料冲蚀损伤断面的形貌特征逐渐恶化,具体表现为拖尾角和表面粗糙度逐渐增大.不同金属材料损伤断面形貌特征具有相似性,但是金属材料属性的差异会对磨料冲蚀过程产生影响,导致条纹在材料损伤断面上的分布和条纹角度出现差异.由于材料损伤形貌特征受控于磨料颗粒运动特性,因此材料冲蚀断面质量改善应该从改变磨料颗粒运动特性角度出发,这为进一步研究材料冲蚀断面质量改进奠定了理论基础.

Characteristics and Generation Mechanism of Metal Damage Morphology by Abrasive Water Jet Erosion

The erosion process produced by pre-mixed abrasive water jet was studied by the experiment and the simulation. The morphology of erosion damage was obtained from the experiment. An erosion model was established based on the Smoothed Particle Hydrodynamics coupling Finite Element Method. By using this model, the erosion process of the material was simulated and analyzed, and the mechanism of the damage morphology of the material was revealed. The results indicate that with the increase of erosion depth, the erosion kinetic energy of abrasive particles decreased, and the erosion angle increased. The erosion damage mode changed from micro-cutting and micro-ploughing to the impact deformation, and the damage morphology characteristics of erosion surface gradually deteriorated, which reflected as increasing declination angle and surface roughness. The damage morphologies of several metals were similar, while the material property had influence on the abrasive erosion process, resulting in the differences of the distributions and the declination angles of striations on the damage surfaces. The material damage morphology was determined by the movement characteristics of abrasive particles, so the quality of the eroded surface should be improved by the control of the movement features of abrasive particles. The study can provide a theoretical basis for the further research on the improvement of material quality of eroded surface.