干摩擦条件下载荷和频率对Cu-15Ni-8Sn合金摩擦磨损性能影响研究

Effect of Load and Frequency on the Tribological Properties of Cu-15Ni-8Sn Alloy under Dry Friction Conditions

目的研究不同摩擦载荷及频率条件下Cu-15Ni-8Sn合金摩擦因数及磨损率的变化规律,探明机械参量变化对合金摩擦学性能的影响机制。方法采用熔炼法制备Cu-15Ni-8Sn合金,在干摩擦条件下对合金进行变载荷/变频率的销盘式往复摩擦实验,并对其摩擦因数、磨损率、磨损形貌及摩擦界面进行形貌及成分分析。结果随摩擦载荷的增大,2种载荷下Cu-15Ni-8Sn合金摩擦因数均呈现先增大后减小的趋势,整体在0.5~0.8之间;磨损体积随载荷的增加而增加;在2 Hz条件下合金的比磨损率随摩擦载荷的增大先降低后升高,在5 Hz条件下合金的比磨损率随摩擦载荷的增大先升高后降低;在高频高载条件下,磨损最为严重。磨痕及摩擦副表征结果显示,在干摩擦条件下,Cu-15Ni-8Sn合金主要以磨粒磨损和疲劳磨损为主;在摩擦过程中,合金基体及对偶同时发生磨损,剥落物以磨屑形式参与摩擦,因此在摩擦界面间发生元素转移。结论在干摩擦条件下,相较于摩擦频率,Cu-15Ni-8Sn合金受摩擦载荷的影响更大。合金磨屑以细小的颗粒状为主,但在低频率、高载荷条件下,会有大块片状磨屑。在干摩擦过程中,对磨副与合金之间会发生相互转移。随着载荷、频率的增加,摩擦层厚度也会变大,且摩擦过程中摩擦层内无剧烈氧化。

The work aims to study the changes of friction coefficient and wear rate of Cu-15Ni-8Sn alloy under different friction loads and frequencies,and investigate the effect mechanism of mechanical parameters on tribological properties of the alloy.Cu-15Ni-8Sn alloy was prepared by melting method.The pin-disk reciprocating friction experiment was carried out to the alloy under dry friction condition at variable loads.The friction coefficient,wear rate,wear morphology and wear morphology and composition of Cu-15Ni-8Sn alloy were analyzed.With the increase of friction load,the friction coefficient of Cu-15Ni-8Sn alloy under two kinds of load increased firstly and then decreased,varying between 0.5 and 0.8,and the wear volume increased with the increasing load.Under the condition of 2 Hz,the specific wear rate of the alloy firstly decreased and then increased with the increase of the friction load.Under the condition of 5 Hz,the specific wear rate of the alloy firstly increased and then decreased with the increase of the friction load.The wear was the most serious under the condition of high frequency and high load.The wear marks and friction characteristics showed that the wear mechanism of Cu-15Ni-8Sn alloy was mainly abrasive wear and fatigue wear under dry friction conditions.During the friction process,the alloy matrix and the friction pair were both worn at the same time,and the exfoliation participated in the friction in the form of abrasive dust,so the element transfer occurred between the friction interface.Cu-15Ni-8Sn alloy is more affected by friction load than friction frequency under dry friction conditions.The alloy chips are mainly fine particles,but under low frequency and high load conditions,there will be large flake chips.In the process of dry friction,there will be mutual transfer between the friction pair and the alloy.With the increase of load and frequency,the thickness of the friction layer will also increase,and there is no severe oxidation in the friction layer during friction.