超音速火焰喷涂制备铝基复合制动盘结构优化设计及分析

Structure Optimization Design and Analysis of Aluminum⁃based Composite Brake Disc Prepared by High Velocity Oxygen Fuel

铝基复合制动盘具有高比强度、良好的导热性、耐磨性及耐蚀性等优点,是轨道交通车辆制动部件的首选。本工作首次提出以7075铝合金(T6)为制动盘基体材料,采用超音速火焰喷涂(High velocity oxygen fuel, HVOF)在其表面制备含WC颗粒增强镍基合金涂层,从而制备出铝基复合制动盘。本工作在基体上设计不同数量、孔径、深度、分布的盲孔,以缓解由于基体与涂层之间热物理性质差异出现的应力,采用有限元软件COMSOL研究盲孔的数量、尺寸、深度及分布对制动盘服役过程中应力分布的影响规律,进而优化制动盘结构设计。模拟结果表明,基体上设计的盲孔一定程度上能够降低制动盘摩擦制动时界面过渡区(ITZ)的热应力;随着盲孔数量增多、孔径和深度增大,等效应力降低;盲孔位置越靠近制动盘内外径边缘,等效应力越小,最小值为87.07 MPa;与孔径、深度相比,盲孔数量对缓解铝基复合制动盘等效应力的效果更为明显。

Aluminum composite brake disc has the advantages of high specific strength,good thermal conductivity,wear resistance and corrosion resistance which is the first choice of brake components for rail transit vehicles.In this work,the 7075⁃aluminum alloy was first used as the matrix material of brake disc with WC particle reinforced Ni⁃based alloy coating was prepared on its surface byhigh velocity oxygen fuel(HVOF).In this work,different number,aperture,depth and distribution of blind holes were designed on the matrix to alleviate the stress caused by the difference in thermal and physical properties between the matrix and the coating.The finite element software COMSOL was used to study the influence of the number,size,depth and distribution of blind holes on the stress distribution during the service of the brake disc,so as to optimize the structural design of the brake disc.The simulation results show that the design of blind holes on the matrix can reduce the thermal stress in the interface transition zone(ITZ)of the brake disc to a certain extent.With the increase of the number of blind holes and the increase of the diameter and depth,the equivalent stress decreases.The closer the blind hole is to the edge of the inner and outer diameter of the brake disc,the smaller the equivalent stress is,and the minimum value is 87.07 MPa.Compared with aperture and depth,the effect of the number of blind holes on relieving the equivalent stress of aluminum composite brake disc is more obvious.