碳化硅陶瓷磨削过程裂纹扩展行为研究

Study on crack extension behavior of silicon carbide ceramic during grinding process

为研究碳化硅材料的磨削机理,进行单磨粒磨削加工实验。结果表明:碳化硅的主要去除方式为脆性去除,同时表面产生横向裂纹。为研究不同尺寸裂纹在加载磨削过程中的损伤行为,采用预置裂纹法进行仿真,结果显示,裂纹的扩展在其尖端应力达到临界值后首先沿裂纹尖端进行扩展,随着应力的进一步增大,裂纹扩展方向发生偏转;在相同情况下大尺寸裂纹的临界扩展应力较低,表面平行裂纹的临界扩展应力小于垂直裂纹。

In order to study the grinding mechanism of silicon carbide material,single grit grinding processing experiments were carried.The results showed that the main removal mode of silicon carbide is brittle removal,while transverse cracks are generated on the surface.In order to study the damage behaviour of cracks of different sizes in the loaded grinding process,the simulation is carried out by using the pre-set crack method,and the results showed that the propagation of cracks first propagates along the crack tip after the stress at the crack tip reaches the critical value.As the stress further increases,the direction of crack propagation deviates.Under the same conditions,the critical propagation stress of large-sized cracks is lower,and the critical propagation stress of surface parallel cracks is smaller than that of vertical cracks.