时变接触特性表面对界面摩擦学行为的影响

通过在锻钢基材表面沟槽中分别填充灰铸铁HT300、Mn-Cu合金和Mn-Cu阻尼合金材料获得具有时变接触特性的表面，并对锻钢光滑表面试样和时变接触特性表面进行摩擦学试验，研究不同时变接触特性表面对界面摩擦学行为(摩擦噪声、摩擦振动以及磨损行为)的影响. 结果表明:填充HT300的时变接触特性表面缓解了界面磨损，有效延续摩擦系统的稳定状态，抑制摩擦振动和噪声的产生；相反，填充Mn-Cu合金和填充Mn-Cu阻尼合金的时变接触特性表面加剧了界面磨损，加速了摩擦系统不稳定状态的出现，进而激发出高强度的摩擦振动和噪声. 在本研究中，摩擦系统失稳引起摩擦振动和噪声主要归因于摩擦磨损过程中黏着撕裂和犁削等界面作用，填充材料的阻尼特性未能起到减振降噪的效果. 

Influence of Time-Varying Contact Characteristic Surface on Interfacial Tribological Behavior

The friction interface is the cradle where the friction-induced vibration and noise originates from; thus, the characteristics of the friction interface are the key factors affecting the friction-induced vibration and noise. Inspired by the mechanism of textured surface suppressing friction-induced vibration and noise, special surfaces which contain variable interfacial contact stiffness and interfacial wear properties were designed. By filling with gray iron HT300, Mn-Cu alloy and Mn-Cu damping alloy materials (Considering that HT300 has damping properties, Mn-Cu alloy and Mn-Cu damping alloy filling materials were also selected in this study in order to clarify the dominant role of the wear characteristics and interfacial interactions and damping characteristics in influencing the friction-induced vibration and noise) into the surface groove of the forged steel substrate obtained the special surfaces with time-varying contact characteristics. Tribological experiments were carried on a self-designed ball-on-flat configuration using the forged steel smooth surface and the time-varying contact characteristic surfaces to study the effects of the time-varying contact characteristic on the interfacial tribological behaviors (friction-induced noise, friction-induced vibration and wear behavior). Time-frequency, sound pressure root-mean-square value, and vibration time-domain signals were acquired and contrasted; the micro-morphology and the profiles of the worn surfaces after the tests were also analyzed by the scanning electron microscope and white light interferometer. By means of a comprehensive comparison, the mechanism of how the time-varying contact characteristic surfaces affected the friction-induced noise was revealed. The results showed that the filler material had a significant influence on the tribological behaviors of the interface. The wear characteristics, contact area and interfacial interactions in the process of interface wear made the interface contact characteristics show certain differences, and the friction vibration and noise induced by the instability of the friction system were also obviously different. In the friction process, the combined effect of the adhesive tearing, ploughing and other interfacial interactions generated at the smooth surface (SS) caused strong fluctuation in the friction force, which triggered the instability of the friction system to produce strong vibration, and radiated high-intensity friction-induced noise. The time-varying contact characteristic surface filled with HT300 (HS) could alleviate the interfacial wear situation and the interfacial interactions, thus stabilizing the friction system without producing significant friction-induced vibration and noise. On the contrary, the time-varying contact characteristic surfaces filled with Mn-Cu alloy (MAS) and Mn-Cu damping alloy (MDAS) aggravated the interface wear and strengthened the interfacial interactions, accelerating the appearance of the unstable state of the friction system, and intensifying the friction-induced vibration and noise. In this study, the unstable friction-induced vibration and noise were mainly attributed to the interfacial interactions such as adhesive tearing and ploughing during the friction process. The changeable interfacial properties caused by the filling materials had a significant effect on the friction-induced vibration and noise performance, but the damping characteristics of the filler failed to reduce the friction-induced vibration and noise.