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High - energy milling process , grinding balls , powder and milling container among strongly collide , resulting powder was adhered to the the grinding ball surface , and milling the inner surface of the container , forming a thin or thick coating . Based on this phenomenon by ball milling the development of material between the principle of cold welding a new surface treatment technology - machinery coating and strengthening of the birth of this technology for the preparation of the metal surface coating technology provides a new research direction. In this paper, a planetary mill , using mechanical coating and enhancement technology TiC coating , were prepared in 2024 aluminum alloy surface of TiC / Al composite coating and Ti / Al / C composite coating , which after two coatings a component mass ratio of 4:1 and 107:30:13 . By scanning electron microscopy ( SEM ) , EDS ( EDS ) , X - ray diffraction (XRD), scratch test , friction and wear experiments were investigated by means of different milling time , the microstructure and mechanical properties of the coating , to explore different coating formation mechanism and evolution . As the milling time , coating thickness , and the apparent density is increased, but the TiC coating , and Ti / Al / C composite coating appeared late in the milling reduction in the thickness of the coating . TiC coating , TiC / Al composite coating and Ti / Al / C composite coating to achieve the thickest coating 27μm, 46μm and 36μm; microhardness of the coating bond strength , friction and wear properties also with ball milling extension of time be increased gradually. The highest milling 12h TiC coating hardness is 478HV0.1 , is more than three times the base hardness ; milling 40h Ti / Al / C composite coating interface critical load largest 56.4N , has a good combination of strength ; TiC / Al composite coating with respect to the TiC coating has a lower coefficient of friction . A powder of a combination of the coating and the substrate as well as within the coating is formed by cold welding , and as the ball milling proceeds , the ball drive powder impact matrix , and gradually deposited onto the substrate to form a coating . Under the continued action of the mechanical force , the coating formed in the brittle TiC powder prone to stress concentration, thereby generating cracks , crack growth resulting surface coating flaking ; ductility of Ti / Al / C powder is formed of the coating its good ductility so that the surface area gradually become integrated , but the the XRD detection is not new phase formation .
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