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采用粉末冶金技术制备铜基复合材料,在制动压力0.5~1.2 MPa范围内,通过定速摩擦试验机研究了干、湿条件下,速度、压力与材料摩擦磨损性能的关系,结果表明:影响摩擦磨损性能的重要因素在于载荷性质和第三体状态。在干摩擦条件下,处于低摩擦速度范围时,摩擦力的静载荷性质使第三体呈疏松状态,这增加了微凸体间的啮合程度而使摩擦系数处于较高值。随第三体致密性增加,其润滑作用增强,微凸体间的机械啮合程度减弱,使材料的摩擦系数和磨损量降低。在高速摩擦时,微凸体间的冲击作用使处于摩擦表层的硬质颗粒容易发生粉碎性破损而弥散分布,这强化了表面强度而使摩擦系数有所增加。摩擦压力对高速摩擦性能影响明显,原因在于高负荷加剧了摩擦面的变形和损伤程度。湿摩擦条件下,水膜的润滑和流动具有降低摩擦系数和增加磨损率的作用主要体现在低速低压条件下。在高摩擦速度和高压力条件下,水分的高温蒸发与离心作用明显,破坏了水膜的存在条件,从而使材料的摩擦磨损性能与干摩擦状态相近。
The powder metallurgy technology was used to prepare copper matrix composites. The relationship between velocity and pressure and the friction and wear properties of the composites under dry and wet conditions was studied by means of a constant speed friction tester under the braking pressure of 0.5 ~ 1.2 MPa. The results show that the influence An important factor in friction and wear properties is the nature of the load and the state of the third body. Under the condition of dry friction, at the low friction speed range, the static load property of the friction makes the third body appear loose, which increases the degree of meshing between the asperities and makes the friction coefficient at a higher value. With the increase of the density of the third body, the lubricating effect is enhanced, the degree of mechanical engagement between the asperities is weakened, and the friction coefficient and wear of the material are reduced. In the high-speed friction, the impact between the asperities to the friction surface of the hard particles prone to comminuted damage and dispersed, which strengthened the surface strength and the friction coefficient has increased. Friction pressure on high-speed friction performance is obvious, because the high load aggravates the friction surface deformation and damage. Wet friction conditions, the water film lubrication and flow with lower friction coefficient and increase the role of wear rate mainly in the low-speed low-pressure conditions. Under the conditions of high friction speed and high pressure, the high temperature evaporation and centrifugation of water obviously destroy the existence conditions of the water film, so that the friction and wear properties of the material are similar to the dry friction state.