陶瓷刀具材料磨损的研究现状

本文重点综述了陶瓷刀具材料显微结构和力学性能对其磨损特性的影响。阐述了陶瓷刀具材料的硬度、强度、断裂韧性和弹性模量等力学性能与其磨损特性的关系,分析了晶粒尺寸、孔隙度和晶间强度对陶瓷刀具材料磨损特性的影响。指出陶瓷刀具材料切削磨损时的基本机理仍然是磨料磨损、粘结磨损、化学反应与扩散磨损。     

显微结构对Y-TZP/Al2O3复合陶瓷磨料磨损性能的影响

以不同Y2O3加入方式(如化学共沉淀和机械混合)制备的Al2O3增强Y-TZP陶瓷(AZD)为研究对象，研究了显微结构对陶瓷耐磨性的影响。结果表明：化学共沉淀法制备的CYADZ与机械混合的MYADZ的硬度和断裂韧性值相近：CYADZ结构均匀、品粒细小，而由于Y2O3的不均分布，MYADZ结构不均、晶粒相差较大。球磨磨料磨损后，CYADZ复合陶瓷较MYADZ复合陶瓷耐磨性好，宏观力学性能如硬度和断裂韧性对陶瓷材料耐磨性的影响应以显微结构为先决条件。     

Effect of Composition and Physical Properties of Silicon Nitride on Rolling Wear and Fatigue Performance

The improved performance of silicon nitride components over all-steel bearings in several applications has been demonstrated. However, the effects of grain size, intergranular phase composition, fracture toughness, and hardness on rolling wear and fatigue performance are not completely understood. Three commercial bearing materials were tested under standard conditions and their physical properties were obtained. Wear and fatigue properties were compared to physical properties and material composition. It was found that a high fracture toughness is not required for high fatigue life and wear resistance. Total wear and fatigue life of the assembly must be considered, in addition to performance of the ceramic material alone, for specific applications. Grain boundary composition did not appear to affect the wear mechanism of these hot-isostatically-pressed materials.     

Abrasive wear performance of various polyamides

Polyamides (PAs) form a major class of tribo-polymers used in almost all types of wear situations. They excel most of the engineering polymers especially in the case of abrasive wear performance. Since methylene (CH₂) to amide (CONH) group ratio in PAs control the physical and mechanical properties, it was thought interesting to examine its influence on tribo-performance also. Hence, two types of PAs (addition and condensation) were selected for the present study. Abrasive wear studies on 10 PAs were done in a single pass condition by abrading a polymer pin against a waterproof silicon carbide (SiC) abrasive paper under various loads. It was observed that CH₂/CONH ratio had a significant influence on various mechanical properties such as tensile strength, elongation to break, fracture toughness, fracture energy and therefore, on the abrasive wear performance. It was observed that CH₂/CONH ratio and various mechanical properties when plotted individually did not show linear relation in most of the cases, while the specific wear rate as a function of some mechanical properties showed good correlation.     

陶瓷材料磨损机制及磨损程度评价方法综述

综合分析陶瓷材料摩擦磨损的机制和影响摩擦磨损的各种因素,如表面加工状况、载荷、速度、时间、温度、润滑等。介绍几种陶瓷材料摩擦磨损程度的评定方法,如用量纲一化参数(最大赫兹接触压力、最大表面粗糙度和断裂韧性的函数Sc,硬度、最大表面粗糙度和断裂韧性的函数S*)大小评价磨损程度,用磨损表面的粗糙度Ry与平均粒径Dg的比值评价陶瓷材料磨损程度,用磨损率评价陶瓷材料磨损程度等。以期指导人们进一步认识陶瓷摩擦磨损的本质规律,有目的地调整材料的性能以提高其耐磨性。     

氮化硅陶瓷球研磨去除机制试验与仿真研究

为研究研磨过程中氮化硅陶瓷球的材料去除形式及磨损行为,结合陶瓷材料动态压痕断裂力学理论,进行陶瓷球研磨加工试验,采用超景深三维显微镜和扫描电镜对研磨后陶瓷球表面进行观察,同时建立单颗金刚石磨粒冲击作用有限元模型并进行仿真研究。试验结果表明:氮化硅陶瓷球表面材料去除以脆性断裂去除和粉末化去除为主,陶瓷球表面残留有大量贝壳状缺陷和呈簇状随机分布的粉末化材料区域;研磨过程中,陶瓷球表面存在擦伤、划伤和凹坑等缺陷;磨粒冲击作用时,表面材料会受微切削作用产生破碎去除,同时也会受挤压作用产生脆性断裂去除,当磨粒以滚动方式作用在陶瓷球表面时,陶瓷球表面更容易形成粉末化去除,且材料去除率更高。仿真结果表明:各磨粒冲击作用方式产生的最大等效应力由大到小的顺序为滚动磨粒变切深、滚动磨粒定切深、磨粒挤压、滑动磨粒定切深,其中,滚动磨粒变切深产生的亚表面裂纹最深。     

MULTI-SCALE AND MULTI-PHASE NANOCOMPOSITE CERAMIC TOOLS AND CUTTING PERFORMANCE

An advanced ceramic cutting tool material Al2O3/TiC/TiN (LTN) is developed by incorporation and dispersion of micro-scale TiC particle and nano-scale TiN particle in alumina matrix. With the optimal dispersing and fabricating technology, this multi-scale and multi-phase nanocomposite ceramic tool material can get both higher flexural strength and fracture toughness than that of Al2O3/TiC (LT) ceramic tool material without nano-scale TiN particle, especially the fracture toughness can reach to 7.8 MPa·m0.5. The nano-scale TiN can lead to the grain fining effect and promote the sintering process to get a higher density. The coexisting transgranular and intergranular fracture mode induced by micro-scale TiC and nano-scale TiN, and the homogeneous and densified microstructure can result in a remarkable strengthening and toughening effect. The cutting performance and wear mechanisms of the advanced multi-scale and multi-phase nanocomposite ceramic cutting tool are researched.     

新型陶瓷喷砂嘴的制备及其应用

分析了喷砂嘴材料和结构的发展情况,采用热压烧结工艺制备出了B4C/(W,Ti)C新型陶瓷喷砂嘴,结果表明随(W,Ti)C含量的增加,陶瓷喷嘴材料的致密度显著增加,晶粒显著细化,保温时间大大缩短,抗弯强度和断裂韧性大大提高;以SiC为冲蚀磨料进行的喷砂冲蚀试验证明了新型陶瓷喷砂嘴的抗冲蚀磨损能力远高于金属、硬质合金和其它陶瓷喷嘴。     

Evaluation of the Machinability of Nickel-Base,Inconel 718, Alloy with Nano-Ceramic Cutting Tools

The machinability of difficult-to-cut aerospace alloys can be enhanced by the rapid development of cutting tool materials that can withstand machining at high-speed conditions. The performance of nano-grain size ceramic tool materials were evaluated when machining nickel base, Inconel 718, in terms of tool life, tool failure modes and wear mechanisms as well as component forces generated under different roughing conditions. Comparison tests were carried out with commercially available ceramic tool materials of micron-grain composition.

The test results show that the micron grain size commercially available tool materials generally gave the longest tool life. The dominant failure mode is nose wear, while some of the nano-ceramic tools were rejected mainly due to chipping at the cutting edge. This suggests that physical properties and mechanical stability of the cutting edge of the ceramic tools influence their overall performance. It is also evident that chemical compositions of the tool materials played a significant role in their failure. The alumina base ceramics are more susceptible to premature fracture than the silicon nitride base ceramics with higher fracture toughness.     

Abrasive wear resistance of some commercial abrasion resistant steels evaluated by laboratory test methods

The aim of the present study is to evaluate the abrasive wear resistance of some potential abrasion resistant steels exposed to different types of abrasive wear contact conditions typical of mining and transportation applications. The steels investigated, include a ferritic stainless steel, a medium alloyed ferritic carbon steel and a medium alloyed martensitic carbon steel.The abrasive wear resistance of the steels was evaluated using two different laboratory test methods, i.e. pin-on-disc testing and paddle wear testing that expose the materials to sliding abrasion and impact abrasion, respectively. All tests were performed under dry conditions in air at room temperature. In order to evaluate the tribological response of the different steels post-test characterization of the worn surfaces were performed using optical surface profilometry, scanning electron microscopy and energy dispersive X-ray spectroscopy. Besides, characterization of the wear induced sub-surface microstructure was performed using optical microscopy.The results show that depending on the abrasive conditions a combination of high hardness and toughness (fracture strain) is of importance in order to obtain a high wear resistance. In the pin-on-disc test (i.e. in sliding abrasion) these properties seem to be controlled by the as-rolled microstructure of the steels although a thin triboinduced sub-surface layer (5–10 μm in thickness) may influence the results. In contrast, in the paddle wear test (i.e. in impact abrasion), resulting in higher forces acting perpendicular to the surface by impacting stones, these properties are definitely controlled by the properties of the active sub-surface layer which also contains small imbedded stone fragments.     

Widerstand gegen abrasiven verschleiss und dynamische bruchzähigkeit weisser vanadingusseisen

The wear behaviour under abrasive sliding loading, the structure and dynamic fracture toughness of white cast iron containing (4 – 6)% V are considered in this paper. In wear systems containing hard abrasive particles (silicon carbide), the dynamic fracture toughness and wear resistance increase with increasing austenite content in the structure. In systems with less hard abrasive particles (e.g. flint, garnet) these alloys exhibit a combination of high fracture toughness and high wear resistance. The vanadium-alloyed white cast irons with a predominantly austenitic matrix show more favourable values with respect to both dynamic fracture toughness and wear resistance in comparison with a simultaneously tested chromium white cast iron.     

The importance of microscopy in studying the wear behaviour of ceramic surfaces

This paper demonstrates how careful microscopy of worn ceramic surfaces can be used to provide information on the mechanisms of material removal. This information is necessary as a critical complement to wear-rate data obtainable from simple wear tests alone (e.g. lapping with diamond grits). Scanning electron microscopy has been extensively used to investigate the changing appearance of worn surfaces as plasticity and fracture processes compete as materials removal and redistribution mechanisms. Examples of the use of secondary electron imaging at different surface tilts, back-scattered electron imaging and stereo imaging are shown. Further, transmission electron microscopy of samples specially prepared to contain the worn surface layer can reveal the presence of phase changes accompanying wear. Furthermore, observations have been made of instances whereby brittle fracture has unexpectedly occurred as a result of repeated plastic deformation of surfaces at low contact severities. Some conclusions are drawn regarding the influence of specimen microstructure, abrasive grit size and environment of the wear of glass-bonded (debased) alumina and titania materials.     

Influence of CrC addition in Ni-Cr-Si-B flame sprayed coatings on microstructure, microhardness and wear behaviour

In the present paper the influence of the addition of chromium carbide (CrC) particles on the microstructure, microhardness and abrasive wear behaviour of flame sprayed Ni-Cr-Si-B coatings deposited on low carbon steel substrate has been reported. Wear behaviour of the coatings was evaluated with a pin-on-block wear system against SiC abrasive medium (120 & 600 grades) over a range of normal load (5–20 N). It was observed that the wear behaviour is governed by the material related parameters (microstructure, microhardness of coating) and test parameters (abrasive grit size and normal load). The addition of CrC reduces the wear rate three to eightfold. Wear resistance was greater against coarse abrasives at high loads than against fine abrasives. Heat treatment of both unmodified (1004) and modified powder (1004-10%CrC, 1004-20%CrC) coatings deteriorated the abrasive wear resistance. SEM study of wear surfaces showed that wear of the coatings largely takes place by groove formation, plowing and scoring. Electron probe micro analysis (EPMA) of the coating was carried out for composition and phase analysis.     

Wear by hard particles

Abrasive wear can be caused by hard particles sliding on a softer solid surface and displaying or detaching material. Different types of interactions are distinguished between the sliding particles and the wearing surface of the solid. Frequently, resistance against abrasive wear is only considered as a function of hardness of the wearing material. However, a more general model shows that, depending on the interaction, the capability of deformation or the fracture toughness of the wearing material is very important in addition to hardness. Abrasive wear resistance can substantially be improved by second phases embedded in a hard or soft matrix. The theoretical models are supported by a lot of experimental results from studies on metallic or ceramic materials.     

Features of wear of brittle inorganic materials during friction and abrasive machining

Laser confocal microscopy reveals fatigue cracking under the surface of silicate glass upon friction and abrasive machining. Surface cracking is also registered and its maximum depth is determined, indicating that its longitudinal cross section has an irregular profile. The stage of fatigue wear of the glass corresponding to debris nucleation shouldbe visualized. It is established that the mass wear rate and the maximum surface cracking depth are correlated: once a definite sliding velocity is reached, the cracking becomes deeper and the wear rate intensifies in both types of tests. The obtained results prove that several wear mechanism can occur simultaneously during abrasive machining of brittle inorganic materials, namely, brittle chipping, low-cycle fatigue, thermomechanical fracture, and local melting (under critical loading conditions).     

原位成型微织构自润滑陶瓷材料的制备及其性能研究

表面织构具有改善表面润滑状态和减摩抗磨的作用,在工程领域的应用也越来越广。现有的微织构加工方法很多,但成本较高,且加工周期长。本试验提出了原位成型的加工方法,以石墨为微织构凸模,设计、加工了沟槽型微织构,经热压烧结工艺将微织构置入到陶瓷粉体中,原位成型表面微织构陶瓷材料。对所得材料进行力学性能测试和摩擦磨损试验,用扫描电镜(SEM)观察裂纹、断面形貌以及磨损表面。结果表明:沟槽型织构材料的断裂韧性和抗弯强度分别为7.4MPa·m~(1/2)和504.8MPa,比无织构材料分别提高了约0.4%和12.3%;沟槽型织构试样摩擦系数较为平稳,且与无织构试样相比,最大摩擦系数和最小摩擦系数分别减少了约33.3%和18.2%;沟槽型织构试样的磨损形式主要是磨粒磨损,无织构试样的磨损形式主要是粘结磨损。     

Tribological behaviour of uni-directionally aligned silicon nitride against steel

Textured silicon nitride, where the β-Si₃N₄ grains were uni-directionally aligned, was fabricated and the effect of anisotropy in microstructure on tribological properties was investigated, compared with a conventional Si₃N₄. The wear tests were carried out for the tribopair of textured silicon nitride ceramic and steel using a block-on-ring tester without lubrication. For the textured Si₃N₄, tribological properties were evaluated in three directions with respect to the grain alignment; the plane normal to the grain alignment and in the directions parallel and perpendicular to the grain alignment in the side plane. The friction coefficient values of each specimen were of the same level under the same sliding conditions. The values of specific wear rate for the plane normal to the grain alignment were lower than those of the other specimens for all sliding conditions. It is considered that the high wear resistance of this plane was caused by restricted microfracture, such as grain dropping and minimal abrasion by wear debris. Both the friction coefficient and specific wear rate were decreased with increasing sliding speed and normal load because of the formation of lubricative FeO between the sliding surfaces.     

Microstructure and performance of multi-dimensional WC-CoCr coating sprayed by HVOF

WC-based coatings deposited by high velocity oxy-fuel (HVOF) spraying have been widely used in many industrial fields, where mechanical components are subjected to severe abrasive wear. Much attention has been especially paid to nanostructured and multimodal WC-based coatings due to their excellent abrasive wear resistance. In this study, a new kind of multi-dimensional WC-10Co4Cr coating, composed of nano, submicron, micron WC particles and CoCr alloy, was developed by HVOF. The microstructure, porosity, microhardness, fracture toughness, and electrochemical properties of the coating were investigated in comparison with nanostructured WC-10Co4Cr coating deposited by HVOF. Abrasive wear resistance of both WC-10Co4Cr coatings was evaluated on wet sand rubber wheel abrasion tester. The results show that the multi-dimensional coating possesses low porosity (0.31 ± 0.09%), excellent microhardness (1126 ± 115 HV_0.3), fracture toughness (4.66 ± 0.51 MPa m^1/2), and outstanding electrochemical properties. Moreover, the multi-dimensional coating demonstrates approximately 36% wet abrasive resistance enhancement than the nanostructured coating. The superior abrasive wear resistance originates from the coating’s multi-dimensional structure and excellent mechanical and electrochemical properties.     

干摩擦条件下3Y-TZP/(Mg,Y)-PSZ陶瓷摩擦副的磨损性能的研究

采用销-盘式摩擦磨损试验机在干摩擦条件下对3Y—TZW(Mg，Y)-PSZ陶瓷摩擦副的磨损性能进行了试验研究。结果表明，3Y-TZP陶瓷的磨损率随着载荷的增加而增大。在低载低速下3Y—TZP陶瓷的主要磨损机制为塑性变形；随着载荷与滑动速度的增加，磨损主要由塑性变形和微断裂造成；在高载高速时，由于对摩偶件(Mg，Y)-PSZ表面的断裂、脱落，形成的磨屑产生磨料磨损对摩擦副表面造成进一步损伤，脆性断裂和磨粒磨损机制是其主要的失效方式。     

Optimum design of cam-roller follower mechanism using a new evolutionary algorithm

Selection of tooling to perform specific operations like drilling and milling on ceramic materials using rotary ultrasonic machining process is an important aspect to meet stringent dimensions on workpiece as well as intended performance of tool. This phenomenon is more critical for micro rotary ultrasonic machining. In the present study, an effort was made to do micro drilling operation of Ø0.3 mm tool with varying geometry, having different wall thicknesses and abrasive grain sizes using design of experiments. The effect of tool-based parameters like grain size and wall thickness has been studied on axial cutting force, radial cutting force, tool wear, edge chipping area and taper. After examining axial and radial cutting forces, it has been concluded that lower wall thickness (80 μm) tool is good for drilling operation; and higher wall thickness (100 μm) tool is good for milling operation under same material removal rate conditions. It has been also investigated that lower wall thickness (80 μm) tool has less edge chipping area and less taper and can impart high drilling depth as compared to higher wall thickness (100 and 150 μm) tool. It is also concluded that lesser grain size (15 μm) tools are advantageous in terms of edge chipping area and cutting force for drilling and milling operations as compared to higher grain size (30, 35 and 45 μm) tool at constant material removal rate. Higher grain size tools have been broken at 1.13 mm³/h material removal rate conditions due to bad profile accuracy. But higher grain size tools have worked fairly well at less material removal rate condition. Higher grain size tools produced less wear. Tool wear was found minimum in higher wall thickness (100 μm) tool having higher abrasive grain size (30 μm). Using inferred results, Ø0.3 mm drilling experiments have been carried out on six aerospace ceramic materials. Also, groove of 0.5 mm size using Ø0.3 mm optimised tool has been successfully carried out in sintered SiC.