Papers by Keyword: Wear Behaviour

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Authors: Hua Fu, Bo Liao, Bao Chen Sun, Ai Ping Liu, Fang Juan Qi, Zhan Lai Ding
Abstract: A semi-metallic stainless steel/carbon fiber reinforced PEEK-based friction material was developed in this paper. The composite was PEEK 19.63wt%, stainless steel fiber 7.57 wt%, carbon fiber 10.97 wt%, cashew 6.51 wt% and fillers 55.33%. The molding process was blending for about 30 seconds at higher speed, pre-heating at the temperature of 80 for 30min, molding at 320 and pressure 35Mpa for 3min/mm, then post-curing at the temperature of 80 for 30min , 150 for 30min270 for 30min320 for 180min. The results of abrasion test showed that the developed material N3 had higher and steady friction coefficient and low abrasion value. The SEM morphology study showed that the wear mechanism was particle abrasion at low temperature but adherence abrasion as well as particle abrasion occurred at higher temperature. The cohesive strength of the composite and the heat-resistant property of resin matrix were the key factors affected wear loss. The abrasion depended on the strength of transformed films and matrix.
Authors: Gu Liu, Gui Ming Chen, Liu Ying Wang, Shao Chun Hua, Jian Xun Yao
Abstract: Samples of AISI 1045 carbon steel were surface hardened by micro plasma transferred arc (PTA) process. The hardened layer was characterized using both light optical and scanning electron microscopy and microhardness techniques. The tribological properties of the surface hardened layer and untreated substrate were investigated using a block-on-ring tribometer sliding against GCr15 steel under unlubricated condition. The worn surface morphologies and dominant wear mechanisms were identified using microscopy techniques. Results show that the surface hardened layer consists mainly of martensite and retained austensite with fine and dense structure, the microhardness of hardened layer increases from approximately HV 200 to HV 600. The wear volume loss of plasma hardened layer was 81.86×10-11m3 much better than that of untreated AISI 1045 carbon steel (743.44×10-11m3). Wear of untreated AISI 1045 carbon steel occurred by combined mechanisms of adhesion, abrasion and plastic deformation. While the worn surface of surface hardened layer is quite better with slight track and thin oxides on the worn surfaces. Plasma surface hardening has essentially changed the wear mechanism of the AISI 1045 carbon steel to slight abrasion and oxidation wear.
Authors: Zhi Hua Chen
Abstract: The natural mulberry silk and high-count combed cotton were chosen as raw materials woven into a thin fabric, with classic colour designed as fashion vertical strips. In dying process, high-quality green dye formulations were used to ensure good quality of yarn; in sizing process, the modified starch based, supplemented by a new polypropylene slurry were combined as sizing, which had high concentration and low viscosity, uniform sizing and improved resistance to mill, reduced the regeneration hairiness; in finishing process, the formaldehyde-free anti-crease finishing agent was applied by wet short steaming process, the fabric had anti-crease property, smooth and non-formaldehyde residue. The material after finishing has firmly quality, smooth and fine, slippery and pleasant, safe and practical, has both the texture and luster of silk, also has the comfort of cotton fabric. Through the selection of raw material, production and finishing process, the eco-environmental was stand out, the colour generous and elegant, excellent performance, good market response. The product development process and wear behavior of this high-grade fabric were described in this article. With the textile low-carbon idea through and living standard’s enhancement, the demand of ecotype textile for consumer is getting more and more broad, for this reason, we have developed new product: the ecotype cotton-silk colur woven taffeta. The natural low tex combed cotton was selected as warp yarn and raw silk as weft, and the colour and style formula were careful designed, the high quality environmental protection dye and the formula in dyeing procedure was selected. In the sizing and after-treatment procedure made the key attract, highlight the green environmental protection performance, the fabric has silky quality and gloss, and has cotton comfort, the colour naturally lofty, has good performance, has good market echo. It satisfied the consumer to lining comfortableness, functionality, artistic request[1]. Presently this product’s development and the production process were shown as follow:
Authors: Jorge Cruz Fernandes, Sergio Pinto, Pedro M. Amaral, Luís Guerra Rosa
Abstract: In the present work a new testing method for assessing the wear resistance of matrix materials employed in the manufacture of diamond tools is presented and discussed. The method allows assessing the wear behaviour of different metallic matrices by simulating a circular cutting action of a tool where, instead of a normal abrasive element (matrix impregnated with diamond) only the matrix material is tested. This method has originated a preliminary model of continuum abrasive contact layer between a rotating circular element made of a metal matrix and a glass material. The model allows the determination of the matrix wear rate at different applied forces. To validate the methodology used, different matrix materials (with different mechanical properties) have been analysed in relation to the experimental wear rate.
Authors: Jing Li, Kuan Yu, Shi Lei, Zhong Quan Ma
Abstract: Fe3Al intermetallics with different Al contents were prepared by mechanical alloying and hot pressing. The phases and dry sliding wear behavior were studied. The results show that Fe3Al bulk materials are mainly characterized by the low ordered B2 structure. The wear resistance increased with increasing Al content, with the lowest volume loss of Fe-32Al and irregular value of Fe-30Al. There were obvious differences in wear mechanisms of sintered Fe3Al under different testing conditions. Under lower loads plastic deformation occurred on the wear surface and the wear performance is mainly particle abrasion, the characteristics of which are micro cutting and furrows. With higher loads, the stress concentration led to rapid crack propagation and eventually the fatigue fracture, which was characterized by brittle split of material.
Authors: Xiu Hua Guo, Ke Xing Song, Shu Hua Liang, Qing Wang, Yong Peng Wang
Abstract: The nano-Al2O3p/Cu composite performed in this paper was prepared by internal oxidation. The nano-Al2O3p/Cu composite wire and the Cu-Ag alloy wire were slid against a copper-based powder metallurgy strip under unlubricated conditions. The wear behavior of nano-Al2O3p/Cu composite and Cu-Ag alloy were researched under different currents from 0~50A and sliding distance from 0~72Km. Worn surfaces of the nano-Al2O3p/Cu composite were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The results indicate that the nano-Al2O3p/Cu composite surface is dispersed with Al2O3 particles having a size of 10~20nm; the wear rate of both 0.60Al2O3p/Cu (containing 0.60wt.% Al2O3) composite and Cu-Ag alloy increases with the increasing electrical current and sliding distance, which increases abruptly at the beginning and smoothly subsequently; The wear rate of Cu-Ag alloy is 2-5 times that of 0.60Al2O3p/Cu composite without electrical current; The wear rate of Cu-Ag alloy is 5-10 times that of 0.60Al2O3p/Cu composite with electrical current of 30A-50A; The sensitivity of electrical current on the Cu-Ag alloy is more apparently than that on 0.60Al2O3p/Cu composite. Adhesive, abrasive, and electrical erosion wear are the dominant mechanisms during the electrical sliding processes.
Authors: S.L. Joy-Yii, Denni Kurniawan
Abstract: This paper reviews the effect of rare earth addition on aluminium-silicon (Al-Si) alloys of hypoeutectic, eutectic, and hypereutectic types. The effects of rare earth on metallurgy, tensile strength, tensile fracture surface and wear behaviour of Al-Si alloys are highlighted and discussed in this paper. It was concluded that adding rare earth element to Al-Si alloys reduces the grain size of primary Si, increases the tensile strength and decreases the friction coefficient decreases. These indicate enhanced mechanical properties for rare earth modified Al-Si alloys are likely.
Authors: Yeong Sik Kim, Kyun Tak Kim
Abstract: This study aims at investigating the effect of the sliding speed and the applied load on the dry sliding wear behavior of thermally sprayed Ni-based self-flux alloy coating. Ni-based self-flux alloy powders were flame-sprayed onto a carbon steel substrate and then these coatings were heat-treated at temperature of 1000 oC. Dry sliding wear tests were performed using the sliding speeds of 0.2, 0.4, 0.6 and 0.8 m/s and the applied loads of 5, 10, 15 and 20 N. AISI 52100 ball (diameter 8 mm) was used as counterpart material. Wear behavior of Ni-based self-flux alloy coatings was studied using a scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). It was revealed that microstructure and wear behavior of the Ni-based self-flux alloy coatings were much influenced by the sliding speed and the applied load.
Authors: Hui Fan
Abstract: Ni-SiC nano-composite coatings with various contents of SiC nano-particulates were prepared by means of the conventional electrodeposition in a nickel-plating bath containing SiC nano-particulates to be co-deposited. The surface morphology and structural constituent in the electrolyte layer were observed by SEM and EDS. The dependence of SiC nano-particulates amount in the nano-composite coatings was investigated in relation to the SiC concentration in bath. The effect of SiC nano-particulate incorporation content on micro-hardness as well as wear-resistance was studied too. The results showed that the nano-Ni-SiC plating layer had smooth and flat surface, uniform microstructure as well as higher micro-hardness and wear-resistance than pure Ni coating. The optimum experimental parameters were derived at condition of, addition of 6g/L SiC nano-particulates in the bath, 40°C temperature, current density of 4A/dm2 , and a stirring rate of 250rpm.
Authors: Pedro M. Amaral, Adriano Coelho, Carlos A. Anjinho, Jorge Cruz Fernandes, Luís Guerra Rosa
Abstract: A test methodology is employed to investigate the cutting behaviour of five different diamond impregnated tools for cutting hard materials, such as rocks. A set of parameters, which characterise the tool wear (specific wear loss in the tool), and its relationship with the cutting force of the examined tools, are established to evaluate the tool wear performance. The procedure established in this work describes the specifications of the equipment used to carry out the tests, the different cutting conditions, the format of the output parameters and the characterisation of the different materials used (binders and rocks), hence allowing to discuss the overall cutting wear behaviour of the tools. The methodology presented indicates a universally applicable procedure for measuring the wear performance of the diamond tools as, at the same time, it establishes a relationship between wear and the mechanical parameters of the different metallic binder materials used to manufacture the correspondent tools. The procedure is proven to be an indispensable instrument for correctly carrying out wear performance tests and for reliably interpreting the wear mechanisms of the tool.
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