Analysis Of Wear Performance After Thermal Cycling Composite Water Medium Based On Bionic Surface Strengthening Of Gray Cast Iron

With the development of railway transportation tending to be high speed and heavy duty in recent years, the situation puts forward higher demands for braking property of the brake discs. In order to improvement the wear resistance of gray cast iron to meet the requirement of demanding tribological application, the laser bionic process has received much attention in recent years due to its application which can enhance the performance of engineering materials. The laser bionic process, combining the bionic theory with the laser process, is regarded as an effective surface treatment technology. Particularly, the aqueous-media bionic laser process, based on the rapid cooling theory, is raised to improve the performance of bionic units, and this achieves a good result that the wear resistance of bionic gray cast iron has been further enhanced, but there are many cracks on the surface of bionic unit. That will reduce its thermal crack resistance. In fact, the service conditions in most cases that brake disc’s working surface is heated and cooled alternately may lead to thermal fatigue failure. In addition, the thermal fatigue cracking on the surface might be detrimental to the wear resistance. For this reason, We analyzed the wear rule of the bionic unit with cracks on bionic specimen, stress—strain 3-D morphology show the bionic unit has little deformation and larger stress. This structure reduces stress on the matrix, result in improving the overall wear resistance. However, the bionic specimen with cracks on the bionic unit has larger deformation than the bionic specimen with no cracks. So the composite treatment of the aqueous-media bionic gray cast iron is applied to reduce the crack number on the bionic units (composite aqueous media bionic treatment), due to its function which can cause the cracks to heal and thus inhibit the crack propagation. Otherwise, the post-thermal-fatigue wear behaviors of the aqueous-media bionic specimen and the composite aqueous-media bionic specimens were investigated in this study. Further study should be conducted to investigate the effect of the cracks before and after thermal fatigue on the wear characteristics of the bionic specimen processed in water. It is also the objective of this work to postulate possible wear mechanisms for different wear conditions.