Effect of scanning strategy of laser ablation on friction and wear properties of textured ductile iron
[Introduction]To improve the wear resistance of ductile iron,the effect of surface texturing by laser ablation with different scanning strategies on friction and wear properties of ductile iron were analyzed.[Method]A regular micro-texture array was prepared on ductile iron surface by traditional spot-by-spot laser ablation,and an irregular micro-texture array was induced in-situ on the surface of ductile iron by continuous laser scanning,both of which had the same average diameter and surface density of micro-texture array. The friction and wear test were then carried out under the condition of oil lubrication. The surface hardness,elemental composition,friction coefficient,and wear rate of two types of textured ductile iron were examined,and their friction reduction and anti-wear property and related mechanisms were discussed.[Result]The spot-by-spot laser ablation method could not improve the surface hardness of ductile iron. The friction coefficient and wear rate of ductile iron textured by spot-by-spot laser ablation were decreased by 9.3％ and 75％ respectively as compared to the untextured one,and oxidation occurred evidently on its surface after friction and wear test. The surface hardness of ductile iron was increased from (273±25) to (428±36) HV by continuous laser scanning method,and the friction coefficient and wear rate were reduced by 20％,and 78％,respectively. The surface oxidation was not obvious after friction and wear test for the ductile iron textured by continuous laser scanning.[Conclusion]The continuous laser scanning method can form a micro-textured surface with better friction reduction and anti-wear property than the spot-by-spot laser ablation method,and also reduce plowing,plastic deformation,and wear debris during friction test. The improvement of tribological properties are attributed to the synergistic effect of the increase of hardness on the untextured surface,the ability of abrasive particle trapping and oil storage in micro-textures,and the dynamic pressure lubrication effect of micro-textures.
万方数据
维普
