The emission of copper-containing particulate matter during braking poses a threat to the natural environment, yet copper plays a crucial role in resin-based brake pads. Developing a copper-free brake pad with high heat-fade resistance has emerged as a significant current topic. This study employs andalusite-filled resin-based brake pads as a replacement for copper in brake pads. It investigates the effects of andalusite mesh size and content on the physical properties, mechanical properties, and tribological wear performance of the brake pads, and explores the wear mechanism of andalusite-filled copper-free resin-based brake pads. The results indicate that adding andalusite to the brake pads enhances their thermal stability, hardness, impact strength, and density, effectively improving the medium-to-high temperature friction coefficient and heat-fade resistance of the brake pads. As the mesh size of andalusite increases, the hardness of the brake pads also increases, while the impact strength initially increases and then decreases. As the weight content of andalusite increases, the hardness and impact strength of the brake pads gradually increase. When the andalusite mesh size is 320 mesh and the content is 20%, the brake pads exhibit good comprehensive tribological wear performance. The addition of andalusite not only increases the medium-to-high temperature friction coefficient of the brake pads but also strengthens their high-temperature friction surface. This study successfully replaces copper, which is harmful to the environment and costly, with andalusite in brake pads, obtaining a high heat-fade resistance metal-free resin-based brake pad.

In this study, epoxy resin (EP) composites were prepared by using molybdenum disulfide (MoS₂) and helical carbon nanotubes (H-CNTs) as the antifriction and reinforcing phases, respectively. The effects of MoS₂ and H-CNTs on the friction coefficient, wear amount, hardness, and elastic modulus of the composites were investigated. The tribological properties of the composites were tested using the UMT-3MT friction testing machine, non-contact three-dimensional surface profilometers, and nanoindenters. The analytical results showed that the friction coefficient of the composites initially decreased and then increased with the increase in the MoS₂ content. The friction coefficient was the smallest when the MoS₂ content in the EP was 6%, and the wear amount increased gradually. With the increasing content of H-CNTs, the friction coefficient of the composite material did not change significantly, although the wear amount decreased gradually. When the MoS₂ and H-CNTs contents were 6% and 4%, respectively, the composite exhibited the minimum friction coefficient and a small amount of wear. Moreover, the addition of H-CNTs significantly enhanced the hardness and elastic modulus of the composites, which could be applied as materials in high-temperature and high-pressure environments where lubricants and greases do not work.

Tool wear is a major cause of accelerated tool failure during the milling of aluminum alloy. The periodically cutting force directly affect the cutting heat and tool wear due to the intermittent cutting characteristics of the milling process. The focus of this paper is to analyze the influence of the variation of cutting force on tool wear behavior. The change law of cutting force by cutting parameters was analyzed firstly. Secondly, the variation of the wear land width (VB) of tool flank face by the milling length was analyzed. Thirdly, the wear morphology and the energy dispersive spectrometer (EDS) results of tool rake face and flank face in different cutting parameters were observed by tungsten filament scanning electron microscope. Finally, considering the cutting force effect, the tool wear mechanism during high-speed milling of Aluminum-Alloy Die Castings 12 (ADC12, 12 means aluminum number 12) was analyzed. The cutting force in tangential direction is predominant during high-speed milling aluminum alloy, which decreases gradually with the increase of cutting speed but increases gradually with the feed rising. The adhesion-oxidation wear was main wear mechanism of tool rake face during high-speed milling. While adhesive wear was the main wear mechanism of the tool flank face during high-speed milling. It is found that the formation of adhesive wear is the process from particle adhesion to melting until the formation of adhesive layer, which related to the change of cutting force.

In this work, a new and effective treatment on bamboo fiber (BF) is presented, and its effect on the interfacial bonding properties of the BF/resin matrix was studied. The interfacial functionary mechanism of rare earth solution (RES) modification to improve the interfacial bonding properties between BF and the resin matrix was analyzed. The hardness and elastic modulus of the interfacial zone between BF and the resin matrix were measured using nanoindentation. Fourier-transform infrared spectroscopy (FT-IR) was used to analyze the change in the surface functional group of BF in the modification process. The surface chemical composition of BF before and after the modification was characterized by X-ray photoelectron spectroscopy (XPS). The results show that the RES modification significantly increases the hardness and elastic modulus of BF and its interfacial zone with the resin matrix. The hydroxyl concentration on the surface of RES-treated BF decreases, which reduces the hydrophilicity of BF. Rare earth ions react with oxygen in the hydroxyl group at the C2 position in the glucosylic ring of cellulose. The RES-modified BF bonds with the resin matrix to form a rare earth complex, which significantly enhances the interfacial adhesion between BF and the resin matrix.