典型激光参数对高硅铝合金缸套表面微坑几何形貌影响

Effect of Typical Laser Parameters on Micro-Dimple Geometry of High-Silicon Aluminum Alloy Cylinder Liner Surface

采用Nd∶YAG脉冲激光器在高硅铝合金缸套表面进行微造型,研究了典型激光参数对微坑几何形貌的影响。随能量密度的增大,微坑直径先增大后保持不变,最大值达到100μm,激光能量密度对凹坑深度的影响较小;微坑直径和深度随着脉冲次数增加均呈先增加后减小趋势,当脉冲数为20时,微坑直径和深度达到最大值,均约为140μm;对高硅铝合金缸套烧蚀阈值进行计算,得到1个脉冲条件下的烧蚀阈值φth=2.08 J/cm^2,因能量累积效应,缸套的烧蚀阈值随脉冲数增加而减小。在微坑深度、直径一定的情况下,不同面积占有率的微织构均能起到减磨的作用,其中10%和20%的面积占有率的减磨效果明显优于5%的面积占有率。

In this study,the Nd∶YAG pulsed laser is used for performing micro-modeling on the surface of a high-silicon aluminum alloy cylinder liner and the influence of typical laser parameters on its micro-dimple geometry is studied.When the energy density increases,the diameters of the micro-dimples initially increase and subsequently remain constant(the maximum diameter is 100μm);the laser energy density only slightly affects the depths of the dimples.The diameters and depths of the dimples initially increase and then decrease with the increasing number of pulses.The maximum diameter and depth of the dimple are 140μm after 20 pulses.Further,the ablation thresholdφth of the high-silicon aluminum alloy is 2.08 J/cm^2 in case of one pulse,which decrease with an increase in the number of pulses owing to energy accumulation.In addition,the effect of microtextures on the wear reduction of the cylinder liner surface can be observed at a fixed depth and diameter of the micropits,and the samples with area fractions of 10%and 20%exhibite better wear properties than those with an area fraction of 5%.