Effect Of Biomimetic Coupling Treatment By Laser With Watermedium On Wear Resistance Characteristics Of Metal Materials

Wear and corrosion and fracture is three kinds of the failure of materials, the main form of failure which accounted for the main part of the material failure,about 70%～80%damage to the equipment,and spare parts are due to various forms of wear and tear caused.Failure caused by wear and tear is not only a lot of waste of materials and components,and may lead to disastrous consequences.Therefore,the research material wear and tear failure mechanism,failure analysis and wear wear control technology failure, not only to enrich and improve the tribology of materials theory,and new technologies to promote the tribology of the birth of new materials,which result in significant economic benefits.Bionics study found that tens of thousands of years to optimize the process of evolution,natural selection organisms always have the greatest environmental adaptability of the surface-coupled form,structure and composition of the surface so that it will have a special performance and functionality,This is a table of various factors of natural organisms the result of coupling.In recent years,the focus group have studied the preparation of biomimetic coupling of materials,to improve the wear-resistant,anti-fatigue and visbreaking properties of material,which achieved very good results.On the basis,we studied on the wear process and wear-resistant mechanism and found that:biomimetic units play a decisive role in the whole process in the performance of materials.To further improve the performance of biomimetic unit,the paper with water instead of air-dielectric media,and selected two commonly used metallic materials,that is,GCr15 bearing steel and graphite cast iron,and treated them by laser biomimetic coupling,and invest whether there are much more improvement.In this article,according to the study of different objects,different samples were prepared as follows:1.For GCr15 bearing steel,by changing the laser energy,frequency, pulse width and the thickness of the water medium,to examine the unit depth and surface quality to determine the optimum processing parameters, inspection parameters in the water medium thickness on the nano-crystalline grain size and wear properties,and processing of air samples under medium compared to study and analyze the phase composition,grain size,surface quality,performance and wear-resistant mechanism.2.For the graphite cast iron,by changing the laser energy,frequency, pulse width and the thickness of the water medium,to examine the unit depth and surface quality to determine the optimum processing parameters, in this parameter,to inspect the effect of the processing media and the water media thickness on the shape,the size,the hardness,the grain refinement and wear resistance property,and analysis the mechanism.Through the experiment,we have the following conclusions:1.The biomimetic units under different medium are composed of two parts of the melting and phase transition zone.The area of bionic body is smaller than others under the water medium,with the increasing thickness of the water medium,the size of unit gradually reduce.For vermicular cast iron,biomimetic unit under the air appeared semicircle shape,and biomimetic unit under water medium inverted parabolic lanes,and both surfaces of them are flat.2.The laser medium to deal with water in the bearing steel can be obtained certain thickness of nano-crystalline structure on the surface of GCr15,and grain size more uniform,which is about 50nm.For vermicular cast iron,aqueous media unit under the bionic organization of regional grain refinement,a number of irregular mesh and the needle-like structures were gradually disappearing;3.The wear resistance properties of biomimetic samples under water media are better,when the water dielectric thickness is 2 mm,the microhardness of biomimetic sample is the highest,and the wear mass loss is least,and the wear resistance is the best;4.Contrast with processed in air,water medium advanced the supercooling.After laser melting,the surface of specimen quickly embraced by water,and the grain nucleation,grow up,the solid-state phase-change process after solidification formed in a very short time,due to a great degree of supercooling,and nucleation rates become larger,and the grain could not grow,and ultimately the formation of nanocrystals,and make the grain of vermicular cast iron obviously refine.5.In the whole process of wear,due to friction and wear of the unit accounted for the vast majority of wear and tear process,therefore,the performance of unit will determine the quality of wear resistance.The structure of the regional organizations of biomimetic unit under water media much more detailed,higher hardness,and had better wear resistance. Compared to air medium,the specimen under water medium double improved the extension time between the friction pair and unit,therefore,its wear resistance better.