灰铸铁作为汽车制动盘的主要制造材料,其表面通常需要提供高而稳定的摩擦系数,但是制动过程中摩擦产生的高温会导致摩擦系数骤降。在灰铸铁动态应变时效(DSA)温度范围内,采用激光喷丸(LP)对灰铸铁表面进行微造型,造型参数分别为不同的深径比和面密度。室温下通过摩擦磨损试验研究了造型样品的几何参数对于材料表面摩擦系数的影响,挑选最佳参数进行高温摩擦试验并讨论了磨损机理。结果表明:温度辅助的激光微造型技术能大幅提高灰铸铁表面的摩擦学性能,造型试样的抗磨损性也优于未造型试样。
Gray cast iron which is widely used in brake discs. The surface of material should has high and stable friction coefficient. However, the frictional heat generated during braking process can lead to the degradation of friction coefficient. The surface texture was fabricated by laser peening (LP) in dynamic strain aging (DSA) temperature regime of gray cast iron, with respect to laser texturing parameters of different dimple depth over ratio of depth to diameter and surface area density. The effects of geometric dimensioning for laser testuring sample on the surface friction coefficient of the material were studied by friction-wear test at room temperature. The optimum parameters were selected to perform high temperature wear test. And then, the wear mechanism was discussed. The results show that the tribological properties improve substantially by laser texturing under temperature assistance. The laser testuring specimens have better abrasion resistance compared with thetexturing samples.