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The tribological properties of materials exhibit a complex and non-linear correlation under varying operational conditions. Therefore, prioritizing a data-driven approach to predict service capability for accelerating material design and preparation is imperative in advancing tribology. The investigation was conducted to analyze the tribological performance and wear mechanism of PTFE composites. The machine learning (ML) approach was concurrently employed to predict tribological properties under diverse operational conditions. The gradient boosting regression (GBR) model demonstrated excellent predictive performance, with R2 of 82% and 91% for the friction coefficient and wear rate, respectively. Furthermore, Pearson correlation coefficient indicated that temperature and speed has a greater impact on friction coefficient and wear rate when compared to load. • The gradient boosting regression (GBR) model demonstrated outstanding predictive performance. • Pearson correlation coefficient indicated that temperature and speed had a greater impact. • With the increase in speed, the friction coefficient and wear rate exhibited a decreasing trend. [ABSTRACT FROM AUTHOR]

A polytetramethylene ether glycol system polyurethane elastomer that meets the TBM main drive sealing requirements was prepared. Based on the working condition of the TBM main drive seal lacking oil lubrication, the wear morphology, wear chemical changes and failure mechanism of the elastomer under different dry friction conditions are mainly explained. The results show that the hydrogen bond content and molecular structure of soft and hard segments of polyurethane elastomer will change when the friction temperature increases, leading to a decrease in mechanical properties and wear failure. With the increase of rotation speed and load, there are different temperature rise trends, wear morphologies and mechanisms, and there is an obvious sudden temperature rise before wear failure, which can be used as an important criterion for seal failure monitoring. • The three stages of change that the polyurethane elastomer material undergoes during the friction and heating process are proposed. • Revealed the influence between friction heat and working conditions parameters during the dry friction process of polyurethane elastomer. • An important criterion for the wear and failure of polyurethane elastomer materials was discovered. • The wear morphology and wear pattern of polyurethane elastomer under different dry friction conditions were explored. [ABSTRACT FROM AUTHOR]

Interfacial issues have always been the top priority of tribology which directly affect tribological performance of friction materials and output characteristics of Ultrasonic Motors (USMs). Therefore, from the perspective of bionics, a series of surface textures with different parameters were designed to regulate friction interface. The tribological properties of textured friction materials were systematically analyzed. The results found that tribological performance was affected by positive and negative aspects. Consequently, there is an optimal parameter in the case of the best tribological behavior. The optimal parameter was obtained by virtue of orthogonal experimental design and matrix analysis based on mathematical statistics. Additionally, the energy conversion efficiency of USMs with textured friction materials compared to untextured samples increased by 29%. • The surface textures were used to increase the energy conversion efficiency of USMs. • The tribological properties of textured friction materials were systematically analyzed. • The reason for the improvement of the output characteristics of the USMs was revealed. • PTFE composites with surface textured show a high potential for using as tribo-materials for USMs. [ABSTRACT FROM AUTHOR]

Improving thermal conductivity is critical for tribological performance but remains a challenge. Here, a 3D structure with layered features is fabricated by electrostatic assembly of h - BN and GO nanosheets. The strategy for structural adjustment from macro to microscopic is beneficial for efficient phonon transport by reducing interfacial thermal resistance, which in turn promotes friction-reduction and wear resistance performance based on "synergistic lubrication". The superiority of the strategy is directly reflected in the excellent self-lubricating, wear-resistance properties, and outstanding thermal conductivity enhancement (1039.16 %) of the composite. Significantly, the comprehensive properties of epoxy-based composites are closely related to macro- and microgeometry of GO and h -BN, helping to reveal the relation between the structural design of multicomponent 2D fillers and tribology-based multifunctionality. [Display omitted] [ABSTRACT FROM AUTHOR]

The friction coefficients of composites prepared by traditional fillers and structure design are usually uncontrollable, which gradually cannot meet the requirements of intelligent response behavior in the modern manufacturing industry. Hence, an epoxy, graphene oxide, and paraffin wax composite (GPEP@ PW) with a network-like sandwich structure was prepared by a four-step method (template method-vacuum impregnation-de-template-vacuum impregnation). Due to sensitive photothermal conversion of GO and excellent ability to control heat (absorption and release) of paraffin wax, GPEP@ PW can respond to near-infrared light to realize the real-time conversion of friction coefficient (0.052 and 0.062), while the wear rate was reduced by two orders of magnitude rate (10−4 to 10−6 mm3/N·m). The light response behavior of tribology under different near-infrared intensities was studied. This strategy is simple and versatile, providing a new idea for the design and preparation of light stimulus-responsive materials to achieve smart tribological properties. [Display omitted] • Ternary hybrid composite with 3D sandwich structure was prepared by a four-step method. • Real-time controllable friction was achieving by structural functionalized photothermal conversion of GO. • The COF changed between 0.052 and 0.062 with NIR switching on and off. • Extremely low wear rate (3.33 × 10−6 mm3/N.m) was got by synergy in GO and paraffin wax. [ABSTRACT FROM AUTHOR]

With the development of energy-saving industries, the tribology and thermal management of composites were increasingly urgent. Here, we explored the dual-network graphene/epoxy composites with enhanced tribological and thermal management. The 3D graphene was prepared using calcium ions as the crosslinker and melamine foam as template. Subsequently, the reinforced concrete-like composites were obtained by dipping in silica-filled epoxy. The research results show that the thermal conductivity of the composites was enhanced by 1015.52% compared to the silica-filled epoxy. Simultaneously, the friction coefficient of the composites was reduced to 0.29 with the wear rate be reduced to 0.19 × 10−5 mm3/N∙m under the condition of 5 N and 2 cm/s. This dual-network model provides a new strategy for the development of solid lubricating materials with excellent thermal management. • The 3D graphene was prepared by template method, using Ca2+ as the crosslinking agent. • The dual-network graphene/epoxy composites were obtained by dipping method. • The thermal conductivity was up to 1.54 W/m∙k with the estimated GMF mass fraction 3.10 wt% • The friction coefficient was reduced to 0.31, with the wear rate was reduced by 97.25%. • Confirmed the key role of thermal conductivity in improving the tribological properties of materials. [ABSTRACT FROM AUTHOR]

Two ways to enhance conversion efficiency of the ultrasonic motor (USM) were developed. According to mechanical and tribological properties, an advanced polyimide (PI) friction material was fabricated. In comparison to conventional polytetraflfluoroethylene (PTFE) friction material, the novel PI friction material enhanced efficiency from 29% to 44%, an improvement of 51.7%. The results indicated high friction coefficient and high elastic modulus were essential for improving efficiency. Inspired by the unique topography, the micro-dimples were introduced into PI friction material which improved the efficiency from 44% to 53%, an increment of 20.5%. The optimum parameter was diameter of 200 μm and area density of 7%. The effect of surface texture on tribological behavior and output characteristic of the USM was comprehensively explored. • The advanced PI friction material and the surface texture enhance efficiency from 29% to 53%, an increase of 82.8%. • High friction coefficient and high elastic modulus are the main reason for improving the conversion efficiency of the USM. • The surface texture enhance the efficiency of the USM because of increased tangential frictional force. [ABSTRACT FROM AUTHOR]

The poor interfacial compatibility between functional fillers and matrix greatly restricts development of polymer composites. Therefore, in the present paper, carbon fibers (CFs) were modified by biomimetic polydopamine (PDA) and amino silane (KH550) to improve interfacial bonding strength with epoxy (EP) substrate. The grafting of PDA and KH550 was divided into "PDA", "PDA-KH550" and "(PDA + KH550)" methods for regulating interfacial compatibility and exploring the reaction mechanism. Improved interfacial strength was beneficial to transfer stress from the matrix to fillers. Consequently, mechanical properties of modified CF/EP were obviously superior to those of unmodified EP/CF. Besides, wear resistance of EP/CF-(PDA + KH550) had an increase of 76%, 67%, 60% and 49% compared to that of EP, CF/EP, CF-PDA/EP and EP/CF-PDA-KH550. Image 1 • PDA and KH550 were used to regulate interfacial compatibility of CF and EP. • The different reaction mechanisms of PDA and KH550 were explored. • The tribological mechanism of modified CF/EP were systematically analyzed. • "CF-(PDA + KH550)" method significantly improved simultaneously the mechanical properties and wear resistance. [ABSTRACT FROM AUTHOR]

To explore the microstructure response to repeated sliding of materials showing stress-induced martensitic (SIM) transformation, we have investigated the microstructure evolution of solutionized Ti-51.5 at.% Ni introduced during the dry sliding against the GCr15 sphere at room temperature. It was found that B19′ was the dominant phase in the worn subsurface of solutionized case exhibiting extremely low martensitic transformation start ( M s ) temperature (lower than −120 °C) and reverse transformation finish temperature ( A f = − 3.4 °C), albeit amorphous structure observed in the topmost layer. Remarkably, nanotwins and faulting were experimentally revealed to contribute to the special microstructure. Moreover, particles of R phase were also discovered. The elementary mechanisms illustrated will be essential for the future modelling of the tribologically deformed layer of the alloys. • The microstructure responses of the solutionized Ti-51.5 at.% Ni to sliding wear have been analyzed by TEM. • Martensite (B19′ and R) was retained at room temperature albeit A f = − 3.4 °C. • Amorphisation was ascribed to faulting in B2 and nanotwins accumulation in B19′. [ABSTRACT FROM AUTHOR]