钼铁合金对铜基摩擦材料摩擦学行为影响研究

发布时间：2018-07-25 14:00

【摘要】：高速列车制动材料具有两个主要目标:一是高且稳定的摩擦系数;二是良好耐磨性。材料成分和摩擦条件是决定摩擦磨损性能的关键,因此,研究其二者对摩擦材料性能的影响有重要的意义。本文采用粉末冶金技术制备了铜-石墨-钼铁合金三组元材料,通过摩擦磨损试验和组织分析,首次探讨了钼铁合金对材料摩擦磨损性能的影响,并讨论了材料在不同摩擦条件下的摩擦磨损性能。研究结果表明:1、钼铁合金含量0-20%间,随着钼铁合金含量增加,摩擦系数和耐磨性提高并趋于稳定。原因在于,硬度较高的钼铁合金发挥硬质点作用,增强基体抗软化能力,降低犁削程度。2、定速摩擦时,摩擦磨损性能受到压力和速度的综合影响。摩擦速度200-1000r/min间,随着压力改变,摩擦表面硬质微凸体的锐度和破碎程度不同,引起摩擦系数波动;摩擦速度处于2500-3000r/min时,压力增加,表面第三体保持连续致密,利于稳定摩擦系数。然而,压力增加引起的温升加剧表面的犁削,增加磨损率。3、变速摩擦时,升速初速度0-末速度3000r/min过程中,随着速度的增加,温度升高,第三体剪切和犁削加剧,导致摩擦系数不稳定;降速初速度3000-末速度0r/min过程中,致密第三体破碎,表面粗糙度变大,摩擦系数增加。4、与干摩擦相比,湿摩擦可降低摩擦系数,同时降低程度与摩擦速度相关。在定速200r/min时,水分良好的润滑和降温作用,干、湿摩擦系数差值约为0.35。随着速度的增加,高温和离心力作用促进水分蒸发并“甩出”摩擦表面,干、湿摩擦系数差距减小为0.1。
[Abstract]:High speed train brake materials have two main objectives: high and stable friction coefficient and good wear resistance. The material composition and friction conditions are the key factors to determine the friction and wear properties. Therefore, it is of great significance to study their effects on the properties of friction materials. In this paper, three component materials of copper-graphite-molybdenum ferroalloy were prepared by powder metallurgy technology. The effect of ferromolybdenum alloy on the tribological properties of the material was discussed for the first time by friction and wear test and microstructure analysis. The friction and wear properties of the materials under different friction conditions were also discussed. The results show that the friction coefficient and wear resistance increase with the increase of the content of ferromolybdenum alloy in the range of 0-20%, and the friction coefficient and wear resistance tend to be stable. The reason is that the molybdenum ferroalloy with high hardness exerts the effect of hard point, strengthens the softening resistance of matrix, reduces the ploughing degree of 0.2, and the friction and wear properties are affected by the pressure and the speed when the friction speed is constant. The friction coefficient fluctuates with the change of pressure between 200-1000r/min and the sharp degree and breaking degree of the rigid convex body on the friction surface. When the friction velocity is at 2500-3000r/min, the pressure increases and the third body of the surface remains continuous and dense. Stable friction coefficient. However, the temperature rise caused by the pressure increases the ploughing of the surface, increases the wear rate. When friction is changed, the initial velocity of the raising speed increases with the increase of the temperature, and the third body shear and the ploughing increase with the increase of the velocity. The friction coefficient is unstable in the process of decelerating initial velocity 3000- final velocity 0r/min, the compact third body is broken up, the surface roughness becomes larger, the friction coefficient increases by .4. compared with dry friction, wet friction can reduce the friction coefficient. At the same time, the degree of reduction is related to the friction speed. At constant speed 200r/min, the difference of dry and wet friction coefficient is about 0.35. With the increase of velocity, high temperature and centrifugal force promote water evaporation and "throw out" the friction surface. The difference between dry and wet friction coefficient is reduced to 0.1.
【学位授予单位】：大连交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U270.35;TB39

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