| Railway is the sinews of national economy, because the transportation is safe and shortcut, and the expense is quick and cheap, moreover, it has finer transport capacity. So, it is one of main vehicles in our national transportation recently. Therefore, it has great value for our national economy to increase the running speed, and many countries devote studying and applying to high-speed railways in the world. The rapid development of high-speed and the degree of high speed are higher and higher. In our country, the railway towards to the higher speed."The higher speed"and"the heavier load"are inevitable trend in development of domestic trains, and train's safe delivery is the key technologies link to develop safety work of the high-speed trains. The traditional materials of brake disks have already couldn't meet the needs. The CGI bearing better thermal conductivity and higher strength, and the cost is inexpensive. Therefore, it is widely used in our country's train brake disc. But, it's wear resistant is insufficiency, which is limited it to further development. Present the train develops to high speed and heavy load, CGI brake disc has been unable to satisfy train's brake request, therefore, on the condition of high speed, in order to satisfy the security and reliability of brake, it is great value to improve the wear resistance of CGI.After a long evolution, the biology has processed to design and to prepare most suited own use the material, which have a structure multiplicity and have a resist well ,and have a high hardness, good wearable, chemical stability higher etc. We have an inspiration from shell surface characteristic and constitution mechanism, according to character and composing of biology, we receive elicitation, and overpass analyze reducing wear and wearable etc. , we mastery and understand on base which model biology coupling rules, which according biologic coupling theory, in the material surface was processed the different shape enhanced unit by laser cladding ceramics, that forms non-smooth shape whose imitating the configuration from the organisms, it was integrated ceramics' hardness with mater's toughness, which through bionics manufacture, we hold that material surface and surface organize configuration and variedly logical enchase of different performance organization, it come into being a new type coupling material which have a good wearable and have a good resist extrusion and resist crack. The ceramic material as an increased friction component is increased the friction coefficient. In this paper the laser cladding and biomimetic coupling jointly apply in brake disc of train, it is opened the new way for the research to be increased of the wear-resistant, heat-resistant and brake-resistant, therefore ,it is increases our country train spare part in the world market competitive advantage.In this research it is uses the method with laser cladding ceramics, laser is processed enhanced units in the CGI brake disc surface, which forms non-smooth surface with intercoupling material and shape,and investigate their wear behavior in the dry sliding process. At last, the anti-wear mechanisms of the biomimetic non-smooth units resist wear are studied. The conclusions are gained as follows:1. Different enhanced units can be shaped on the surface of materials with the help of the laser cladding, which are made up of cladding region, melting region and heat influence region. This three zones as a result of coating material's difference, the organization have the change, but the rule is similar. The structure of the cladding zone is thiny and dense; the structure of the cladding near base and melting is thick, the structure of melting zone mainly is ledeburite. The structure of the heat influence region is martensite and graphite, the melting zone and substrate forms the good martensite union.2. West tests suggest that the wear-resistances are improved by processing designed biomimetic enhanced units on the surface of the CGI specimens, and the wear-resistances of cladding by laser is better than melting, the friction coefficient is improved. The wear-resistances vary along with the cladding material, the laser processing energy density, the modes of unit embedding into the matrix and the unit distributing. With the cladding material and the laser processing energy density increasing, the wear-resistances improve accordingly. For the different modes of unit embedding into the matrix, the gridding has the best wear-resistance, the dam is the second. The wear-resistance varies with the distributing space and angle of enhanced unit varying. When the distributing space is 1, 2, 3mm, with the distributing space broadening, the wear-resistance of non-smooth specimen is worse accordingly. The enhanced units with distributing 45°shows the best wear-resistance. The friction coefficient is effected with the material nature and surface roughness.3. The wear-resistances of the enhanced specimens under the different loads and against different hardness friction pairs. With the loads increasing, the untreated and enhanced specimens take the same rule, the wear-resistances are worse gradually, the friction coefficient is decreases. And with the difference of the hardness between the specimens and friction pairs, the wear-resistances improve accordingly. But the wear-resistances of the units against the friction pairs vary along with the cladding material, the laser processing energy density, the modes of unit embedding into the matrix and the area ratio of the enhanced units increase accordingly, as a result of that the wear behavior between the enhanced units and the friction pairs become worse, and the difference of the wear-resistance decease accordingly. The difference of wear-resistance varies with the distributing space and angle of enhanced unit varying.4. The enhanced units play a decisive role on improving the wear-resistance of the enhanced specimens. When the enhanced units is in the wear process(two), it can be gotten from the free-body conditions of the enhanced units, with the area ratio of the enhanced units, increasing, the average load force on the single units decreases accordingly, so the friction force is little. As a result of that, the wear behavior of the enhanced units is better, and the extent of wear-resistance is improved much more. The theory can explain the condition of the different laser processing density, different modes of the enhanced units embedding into the matrix and the different distributing space. Concerning the distributing angle of enhanced unit( 0°,45°,90°), the unit distributing 0°can't resist material transfer and accelerate the speed of wear; the wear-resistance is the worst among the non-smooth specimens with different distributing angle. The vertical impact force on the front edge of unit distributing 45°is smaller than that of unit distributing 90°; the speed of wear is the slowest.5. The wear process between the enhanced specimens and the friction pair can be disported three steps: First, the friction pair contacts with raised part of the enhanced unit close under the load before the wear. When the wear is beginning, the friction pair wears against the raised part of enhanced units, the raised part is so little that it can be worn out quickly, the friction pair begins to wear the matrix and enhanced units sunchronously very soon. Because of the matrix is softer and the wear-resistance is worse, the wear extent of the matrix worse than that of enhanced units under the same wear condition. After a while, the enhanced units will come out from the matrix and are higher than matrix again. The enhanced units will support the friction pair and wear against the friction pair solely. Then the enhanced units will be worn out, the friction pair will wear against surface mixed by the non-smooth units and matrix again. The above-mention process will be repeated again and again as far as the units existing.
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