{"title":"Influence of large deformation on plastic yield inception and associated mechanism during spherical indentation of soft materials","authors":"Hao Yuan , Xiaochun Yin , Huaiping Ding , Liang Jiang , Changliang Wang , Hao Zhou , Cheng Gao , Xiaoao Chen , Junti Wang , Hui Wang , Wenhao Xie","doi":"10.1016/j.triboint.2025.111315","DOIUrl":"10.1016/j.triboint.2025.111315","url":null,"abstract":"<div><div>Soft materials typically experience large deformations before the onset of plastic yielding during indentation. The inception of plastic yield and associated mechanisms are significantly different from those of hard materials under small deformation, where the influences of large deformation are investigated in this paper. A parametric finite element model is developed to solve the indentation of elastic-plastic soft half-spaces by rigid spherical indenters, encompassing a wide range of soft materials. The stress and deformation fields at the onset of plastic yielding, along with the critical contact parameters for initial yield, are accurately determined. A soft material range, referred to as the FYD range, in which finite deformations are required for initial yield, is identified. Within the FYD range, the characteristics of the stress field exhibit alteration, the individual stress components reduce unevenly, the Mises stress substantially changes, and the load and indentation needed for plastic yielding inception significantly reduce. The interaction between large deformation and frictional traction results in significantly different yield behaviors compared to those observed in hard materials at small deformation. Three novel yield deformation mechanisms are found to be universal and driven by large deformations. These include the significant compression of the stress concentration region, significant flattening of the stress concentration region, and the occurrence of a partial tension zone on the contact surface. Large deformations strongly influence the mechanisms associated with the inception of plastic yield, revealing unique plastic yield behaviors in soft material indentation. These findings provide new insights into the physics of soft material indentation under large deformations.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"214 ","pages":"Article 111315"},"PeriodicalIF":6.1,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145323847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Zhou , A.K. Gupta , K. Bi , A.S. de Wijn , P. Schall
{"title":"Superlubric sliding in a multi-contact fullerene-molybdenum disulfide heterostructure","authors":"D. Zhou , A.K. Gupta , K. Bi , A.S. de Wijn , P. Schall","doi":"10.1016/j.triboint.2025.111317","DOIUrl":"10.1016/j.triboint.2025.111317","url":null,"abstract":"<div><div>Recent research shows that superlubric 2D materials offer great potential for friction reduction, yet their requirements of flatness and small scale hinder real-world applications. Here, we study a multi-contact van der Waals heterostructure, composed of fullerene (C<sub>60</sub>) molecules sandwiched between molybdenum disulfide (MoS<sub>2</sub>) atomic layers by molecular-dynamics simulations. We show that despite the multi-contact geometry, the confined layer of C<sub>60</sub> nanoparticles exhibits superlubric behavior at high fullerene density or high applied normal force, where the fullerenes’ rotational degrees of freedom are suppressed and the MoS<sub>2</sub> layer slides over the fullerenes. At lower fullerene density or load, fullerene rolling leads to increased frictional dissipation. We demonstrate that the atomic stacking at the fullerene-MoS<sub>2</sub> contact evolves from aligned into misaligned with increasing fullerene coverage, reflecting the increasing fullerene-fullerene interactions suppressing their rolling degrees of freedom. Thus, counterintuitively, in the fullerene-MoS<sub>2</sub> heterojunction system, rolling of the fullerenes is not beneficial for friction reduction, as superlubric slip offers an alternative, lower-friction mechanism. These results on the multi-contact sliding of a heterojunction of fullerene nanoparticles and 2D material are useful for guiding nanoscale superlubric properties into macroscopic scale superlubric applications.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"214 ","pages":"Article 111317"},"PeriodicalIF":6.1,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145323841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A method of self-healing hydrophobic organic coating with gradient texture implantation: Tackling the challenge of bearing corrosion and friction","authors":"Jiahe Wang, Qunfeng Zeng, Zeming Pang","doi":"10.1016/j.triboint.2025.111325","DOIUrl":"10.1016/j.triboint.2025.111325","url":null,"abstract":"<div><div>Bearing steel needs protection in marine environments due to its extreme lack of corrosion resistance. However, traditional anti-corrosion coatings face the problem of friction damage. This study proposes a method for self-healing hydrophobic organic coatings implant gradient texture, avoiding the harm of severe wear to the coating. Nano-SiO<sub>2</sub> modified stearic acid coating reduces the friction coefficient of bearings from 0.8 to 0.35 (room temperature) and below 0.1 (high temperature). The stearic acid with state change at high temperatures have a synergistic effect with ester lubricants, which has a lubrication enhancement effect exceeding 20 %. The regeneration behavior of the stearic acid layer is influenced by both metal chemical adsorption and oil interface diffusion. The gradient texture of laser secondary processing changes the equilibrium point of the reaction through anchoring and increasing the area. The additional fluid dynamic pressure generated by the asymmetrical pit texture enhances the lubrication effect. The adsorption rate in finite element simulation is 90 %, and the regeneration rate in the experiment is as high as 98 %, which proves the feasibility of using coatings on the bearing surface. This study provides new ideas for the corrosion and wear protection of bearings under harsh working conditions.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"214 ","pages":"Article 111325"},"PeriodicalIF":6.1,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145323846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kaikui Zheng , Faxuan Zheng , Jingyi Lin , Zhiying Ren , Youxi Lin
{"title":"Utilization of red mud as copper substitute in eco-friendly resin-based brake composites: Performance evaluation and machine learning prediction","authors":"Kaikui Zheng , Faxuan Zheng , Jingyi Lin , Zhiying Ren , Youxi Lin","doi":"10.1016/j.triboint.2025.111324","DOIUrl":"10.1016/j.triboint.2025.111324","url":null,"abstract":"<div><div>Red mud, a highly alkaline industrial solid waste generated during the production of alumina, poses significant environmental challenges due to its massive stockpiling. This study proposes a novel strategy to utilize red mud as a filler in copper-free resin-based brake composites, aiming to replace environmentally problematic and costly copper. This approach not only offers a pathway towards copper-free brake composites but also presents a potential solution for the eco-friendly disposal of red mud. The effects of red mud content on the physical properties, mechanical properties, and friction-wear performance of the composites were systematically investigated, coupled with a comprehensive analysis of the wear mechanisms. Results indicate that incorporating an appropriate amount of red mud enhances the density, hardness, and impact strength of the composites. Crucially, it effectively improves the friction coefficient at medium to high temperatures, mitigating thermal fade. While density and hardness increased proportionally with red mud content, impact strength exhibited a complex non-linear trend, initially decreasing, then increasing, before decreasing again. The composite containing 35 wt% red mud demonstrated the most favorable overall friction-wear performance. An optimized formulation was derived using Response Surface Methodology (RSM): 18 wt% phenolic resin, 5 wt% bamboo fiber, 15 wt% alumina, 39 wt% red mud, 3 wt% graphite, 5 wt% nitrile rubber powder, and 15 wt% barium sulfate. This formulation maintained a stable friction coefficient between 0.48 and 0.50 across a test temperature range of 100 ∼ 350 °C. Furthermore, five machine learning methods were employed to establish predictive models correlating the composite formulation with the friction coefficient. Cross-validation revealed that the Particle Swarm Optimization-Back Propagation (PSO-BP) neural network exhibited the best generalization capability on the test set (<em>R</em>² = 0.87284, prediction accuracy = 97.5987 %), identifying it as the optimal prediction model. This study successfully demonstrates the feasibility of using red mud to replace copper in brake composites, yielding high-performance, eco-friendly, copper-free resin-based brake composites.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"214 ","pages":"Article 111324"},"PeriodicalIF":6.1,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145323853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Friction and chemical action of deionized water on microscopic wear of sapphire surface","authors":"Hongguang Deng, Min Zhong, Meirong Yi, Xiaobing Li, Jianfeng Chen, Wenhu Xu","doi":"10.1016/j.triboint.2025.111320","DOIUrl":"10.1016/j.triboint.2025.111320","url":null,"abstract":"<div><div>Nano wear testing of C-directional single crystal sapphire was conducted using atomic force microscopy in deionized water. The friction and chemical action of deionized water on the micro wear of sapphire was studied by comparing it with the anhydrous ethanol environment. The experimental results indicate that deionized water has both positive and inhibitory action on the micro wear of sapphire materials. It is closely related to the sliding speed of the probe tip. In the low sliding speed range, deionized water has a negative influence on the surface wear of sapphire. When the sliding speed reaches 4 μm/s, the average wear depth of sapphire surface in deionized water is significantly improved. In addition, the influence of cycles on micro wear of sapphire surface is not related to the liquid environment of the contact interface. When the load is 0.24, 0.96, and 2.40 μN, the surface wear depth of sapphire in deionized water is 128 %, 48 %, and 35 % higher than that in anhydrous ethanol, respectively. The promoting effect of deionized water on the removal of sapphire is attributed to the Si-O-Al bridge bond formed between the silicon tip and the substrate. Besides, the soluble substance (Al(OH)<sub>4</sub><sup>-</sup>) is generated by the reaction between the sapphire surface and water. The research results can provide reference for understanding the mechanical and chemical wear of sapphire.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"214 ","pages":"Article 111320"},"PeriodicalIF":6.1,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145323842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiawei Wang , Zexi Shao , Ji Liu , Yugang Miao , Zhengwu Yao , Tao Jiang , Bintao Wu
{"title":"TiNiCuZrNbTa refractory high entropy alloy coatings fabricated using laser cladding: Microstructure and tribological behavior","authors":"Jiawei Wang , Zexi Shao , Ji Liu , Yugang Miao , Zhengwu Yao , Tao Jiang , Bintao Wu","doi":"10.1016/j.triboint.2025.111319","DOIUrl":"10.1016/j.triboint.2025.111319","url":null,"abstract":"<div><div>Aerospace copper alloy components typically require high wear resistance at surface connections to withstand substantial mechanical loads. In this study, a new refractory high-entropy alloy Ti<sub>35</sub>Ni<sub>34</sub>Cu<sub>10</sub>Zr<sub>10</sub>Nb<sub>8</sub>Ta<sub>3</sub> coating was fabricated on copper substrate via laser cladding and its microstructral characteristics and tribological behaviors were fully explored to enhance surface durability. The results show that the obtained coatings exhibit a dense, defect-free microstructure with strong interfacial bonding, composed predominantly of TiNb, TiCuNi, and Zr<sub>14</sub>Cu<sub>51</sub> phases. These features contributed to a significant improvement in wear resistance compared to conventional high entropy alloy. It is recognised that the presence of TiO<sub>2</sub>, ZrO<sub>2</sub>, Nb<sub>2</sub>O<sub>5</sub>, and Ta<sub>2</sub>O<sub>5</sub> in the composite structure promoted the formation of a stable oxide layer during wear. The synergistic deformation behavior of these metal oxides helped reduce strain localization, thereby enhancing the coating’s durability. The research outcomes establish a viable strategy for tailoring the surface architecture of copper-based components, offering a pathway toward extended operational lifespans in harsh environments.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"214 ","pages":"Article 111319"},"PeriodicalIF":6.1,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145323843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhanghao Yang , Shurui Huang , Lei Lei , Qiwei Zhu , Shaohu Liu , Ming Yang , Runqi Zhang , Yan Xiong , Wenxing yang
{"title":"Tailoring an abnormal gradient with nano-dislocation networks via hybrid laser-quenching/USRP: A breakthrough in wear resistance of steel","authors":"Zhanghao Yang , Shurui Huang , Lei Lei , Qiwei Zhu , Shaohu Liu , Ming Yang , Runqi Zhang , Yan Xiong , Wenxing yang","doi":"10.1016/j.triboint.2025.111313","DOIUrl":"10.1016/j.triboint.2025.111313","url":null,"abstract":"<div><div>Dynamic sealing interfaces of petroleum plug valves suffer severe wear-induced failure under extreme conditions, necessitating alternatives to traditional carburization—a process limited by interfacial brittleness, multi-step pollution, and low automation. This study proposes a hybrid process combining Laser Quenching (LQ) and Ultrasonic Surface Rolling Process (USRP) to fabricate a multiscale-strengthened layer on AISI 4140 steel. The layer exhibits a unique \"anomalous grain gradient–nano dislocation architecture\" accompanied by carbon supersaturation. While LQ produces a hardened layer reaching 800 μm in depth, thermal boundary effects lead to anomalous grain coarsening at the surface (surface martensite: 2.74 μm vs. subsurface: 1.58 μm). USRP effectively counteracts this through high-frequency dynamic strain, implanting a high-density nano-dislocation network into coarse martensite. This results in an exceptional nanohardness exceeding 10 GPa, challenging the classical \"coarse-grain softening\" paradigm. The wear volume is reduced by 74.4 %, attributed to three synergistic mechanisms: an ultra-high strength barrier (combining nano-dislocation cell pinning and carbon-supersaturated martensite) that confines plastic deformation to sub-micron depths, suppressing material loss at its source; a hard gradient-supported tribo-oxide layer reducing friction and preventing direct metallic contact; and a wear-adaptive response involving dislocation-cell-catalyzed martensite nanonization and stress-induced ω phase transformation, establishing a self-reinforcing cycle of \"damage→nanonization/phase transformation→hardening\". These mechanisms achieve profound coupling through a \"pre-engineered gradient–hard substrate-supported oxide formation–dynamic adaptive response\" framework. This work advances theoretical understanding of non-equilibrium structural evolution under multi-field coupling while delivering an adaptive, transformative, and environmentally sustainable surface strengthening solution for petroleum valves and critical engineering components.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"214 ","pages":"Article 111313"},"PeriodicalIF":6.1,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145319860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A nonlinear dynamic model for non-contact mechanical seals with fluid-solid-thermal coupling effects","authors":"Xiang Zhao, Ying Liu, Hongju Li","doi":"10.1016/j.triboint.2025.111311","DOIUrl":"10.1016/j.triboint.2025.111311","url":null,"abstract":"<div><div>The dynamic characteristics of non-contact mechanical seals are affected by multi-physics and secondary seal non-linearities, which are ignored in traditional dynamic models. As a result, it struggles to accurately predict dynamic response of sealing systems under actual operating environments. To overcome these limitations, this work aims to propose an advanced dynamic model that integrates the fluid-thermal-solid coupling and nonlinearities of secondary seal. Based on the results of steady-state multi-physics coupling calculations, the transient data set of the primary seal is obtained using the perturbation method. A surrogate model between film thickness and dynamic parameters is established using machine learning method. The existing nonlinear model of the secondary seals is discretized and expressed numerically. A co-simulation solution method of the dynamic model is introduced to enable rapid calculation of dynamic responses. To verify the accuracy of the model, a novel method to measure performance parameters and dynamic responses of the mechanical seal is also proposed by applying force perturbation. The effectiveness of the proposed model is proven through comparisons with several experiments. The analysis reveals that the sealing system has good interference resistance and stability with design parameters. The hysteresis effect of the secondary seal is one of the key factors affecting tracking performance, which increases the risk of end-face wear and excessive leakage. This work provides theoretical guidance for multi-physics coupling and dynamic modelling of non-contact mechanical seals, laying the model and method foundation for failure analysis.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"214 ","pages":"Article 111311"},"PeriodicalIF":6.1,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145323845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zeyun Wang , Zhenyu Zhang , Yujie Chen , Jingsheng Luo , Jiang Li , Jianjun Hu , Longliang Huang , Pengfei Hu , Haisong Huang
{"title":"Atomic surface of AlSi10Mg produced by novel green chemical mechanical polishing using hybrid abrasives and material removal mechanism elucidated by nanoscratching","authors":"Zeyun Wang , Zhenyu Zhang , Yujie Chen , Jingsheng Luo , Jiang Li , Jianjun Hu , Longliang Huang , Pengfei Hu , Haisong Huang","doi":"10.1016/j.triboint.2025.111310","DOIUrl":"10.1016/j.triboint.2025.111310","url":null,"abstract":"<div><div>A new green chemical mechanical polishing (CMP) was developed for AlSi10Mg, including hybrid abrasives of silica, yttria and ceria, polyethylene glycol, sodium metasilicate, threonine and hydrogen peroxide. After CMP, atomic surface with surface roughness Sa of 0.174 nm is achieved, and material removal rate is 21.57 μm/h. Transmission electron spectroscopy (TEM) confirms that the thickness of damaged layer is 3.4 nm. To the best of our knowledge, surface roughness and thickness of damaged layer of AlSi10Mg are both the lowest, compared with those published hitherto. Nanoscratching was conducted by molecular dynamics simulations. When the nanoscratching depth decreased from 3 to 2 nm, the thickness of damaged layer reduced from 3.9 to 3.4 nm, which agrees well with characterizations of TEM.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"214 ","pages":"Article 111310"},"PeriodicalIF":6.1,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145319705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaoxu Liu , Yuya Nakamura , Masato Yamanaka , Satoru Maegawa , Haruka Sasai , Shingo Ono , Fumihiro Itoigawa
{"title":"Amorphous carbide layer formation on medium-carbon steel via short pulse laser in PAO oil for enhanced tribological performance","authors":"Xiaoxu Liu , Yuya Nakamura , Masato Yamanaka , Satoru Maegawa , Haruka Sasai , Shingo Ono , Fumihiro Itoigawa","doi":"10.1016/j.triboint.2025.111312","DOIUrl":"10.1016/j.triboint.2025.111312","url":null,"abstract":"<div><div>This study presents a laser-assisted surface modification method enabling in-situ carburization of medium-carbon steel in hydrocarbon oil. Sub-nanosecond pulses generate transient high-temperature zones, with the oil acting as both carbon source and quencher. XRD shows a weak broad peak at ∼41.4° assignable to Fe<sub>3</sub>C/Fe<sub>5</sub>C<sub>2</sub>, consistent with TEM observation of a 50–200 nm amorphous carbide layer. The process maintains surface smoothness (Ra < 0.10 µm), nearly doubles hardness, and yields extended low-friction lifetimes in oil as well as reduced friction in dry sliding. Raman analysis further indicated that the amorphous Fe–C layer contains minor carbonaceous species which evolve into a carbon-rich tribofilm during sliding, supporting the intrinsic lubricity of the amorphous phase.</div></div>","PeriodicalId":23238,"journal":{"name":"Tribology International","volume":"214 ","pages":"Article 111312"},"PeriodicalIF":6.1,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145324583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}