Interface Wear Research Articles

Synergistic effects of fiber/matrix interface wear and fibers fracture on matrix multiple cracking in fiber-reinforced ceramic-matrix composites

ABSTRACTIn this paper, the synergistic effects of fiber/matrix interface wear and fibers fracture on matrix multiple cracking in fiber-reinforced ceramic-matrix composites (CMCs) are investigated using the critical matrix strain energy (CMSE) criterion. The shear-lag model combined with the fiber/matrix interface wear model, fibers fracture model and the fiber/matrix interface fracture mechanics debonding criterion is adopted to analyze the fiber and matrix axial stress distribution inside of the damaged composite. The relationships between the matrix multiple cracking, fatigue peak stress, applied cyclic number, fiber/matrix interface wear and debonding and fibers failure are established. The effects of fiber volume fraction, fiber/matrix interface shear stress, fiber/matrix interface debonded energy, cycle number, fatigue peak stress and fibers strength on matrix multiple cracking evolution are discussed. Comparisons of matrix multiple cracking with/without cyclic fatigue loading are analyzed. The experimental multiple matrix cracking of unidirectional SiC/CAS, SiC/CAS-II, SiC/Borosilicate and mini-SiC/SiC composites with/without cyclic fatigue loading are predicted.

Fatigue life prediction of ceramic-matrix composites

PurposeThis paper aims to predict fatigue life and fatigue limit of fiber-reinforced ceramic-matrix composites (CMCs) with different fiber preforms, i.e. unidirectional, cross-ply, 2D-, 2.5D- and 3D-woven, at room and elevated temperatures.Design/methodology/approachUnder cyclic loading, matrix multicracking and interface debonding occur upon first loading to fatigue peak stress, and the interface wear appears with increasing cycle number, leading to degradation of the interface shear stress and fibers strength. The relationships between fibers fracture, cycle number, fatigue peak stress and interface wear damage mechanism have been established based on the global load sharing (GLS) criterion. The evolution of fibers broken fraction versus cycle number curves of fiber-reinforced CMCs at room and elevated temperatures have been obtained.FindingsThe predicted fatigue life S–N curve can be divided into two regions, i.e. the Region I controlled by the degradation of interface shear stress and fibers strength and the Region II controlled by the degradation of fibers strength.Practical/implicationsThe proposed approach can be used to predict the fatigue life and fatigue limit of unidirectional, cross-ply, 2D-, 2.5D- and 3D-woven CMCs under cyclic loading.Originality/valueThe fatigue damage mechanisms and fibers failure model were combined together to predict the fatigue life and fatigue limit of fiber-reinforced CMCs with different fiber preforms.

Effect of Friction Heat on Interfacial Wear and Brake System Stability

Effect of Friction Heat on Interfacial Wear and Brake System Stability

Study on the Correlation Between Dynamical Behavior and Friction/Wear Mechanism Under the Effect of Grooves

In this work, the interfacial friction and wear and vibration characteristics are studied by sliding a chromium bearing steel ball (AISI 52100) over both multi-grooved and single-grooved forged steel disks (20CrMnMo) at low and high rotating speeds in order to reveal the effect mechanism of groove-textured surface on tribological behaviors. The results show that the grooves modify the contact state of the ball and the disk at the contact interface. This consequently causes variations in the normal displacement, normal force, and friction force signals. The changes in these three signals become more pronounced with increasing groove width at a low speed. The collision behavior between the ball and the groove increase the amplitude of vibration acceleration at a high speed. The test results suggest that grooves with appropriate widths could trap wear debris on the ball surface while avoiding a strong collision between the disk and the ball, resulting in an improvement in the wear states.

Understanding Wear Interface Evolution to Overcome Friction and Restrain Wear of TiAl–10 wt%Ag Composite

The main objective of this paper is to study wear interface evolution for analyzing the of friction and wear property of TiAl–10 wt%Ag composite. The results show that the friction coefficient and wear rate of TiAl–10 wt%Ag rapidly reduce at 0–25 min and rhythmically fluctuate at 25–60 min. TiAl–10 wt%Ag at 60–240 min obtains low friction and less wear. It is concluded that silver with the low shearing strength of about 125 MPa shows the eminent plastic deformation on wear interface. It effectively reduces friction resistance and material loss, cause TiAl–10 wt%Ag to obtain low friction coefficient, and less wear rate at 0–25 min. Increased silver content, reduces oxide content, and varies wear mechanisms cause the repeating variation of friction resistance and material loss, which results in the rhythmical fluctuation of friction coefficient and wear rate at 25–60 min. High silver contents exist on smooth wear interfaces, exhibit the eminent plastic deformation to lower friction and reduce wear. TiAl–10 wt%Ag obtains the low friction and less wear at 60–240 min.

Damage development and lifetime prediction of cross-ply ceramic-matrix composites subjected to cyclic loading at room and elevated temperatures

ABSTRACTIn this paper, the damage development and lifetime prediction of fibre-reinforced ceramic-matrix composites subjected to cyclic loading at elevated temperatures in oxidising atmosphere have been investigated. Considering the damage mechanisms of matrix cracking, interface debonding, interface wear and interface oxidation, the damage evolution of fatigue hysteresis dissipated energy, fatigue hysteresis modulus, fatigue peak strain, interface shear stress and broken fibres fraction have been analysed. The relationships between damage parameters and internal damage of matrix cracking, interface debonding and slipping, and fibres fracture have been established. The experimental fatigue hysteresis, interface slip lengths, peak strain, and the fatigue life curves of cross-ply CMCs under cyclic loading at elevated temperature have been predicted. The different fatigue behaviour in unidirectional and cross-ply CMCs at room and elevated temperatures subjected to low-cycle and high-cycle fatigue has been discussed.

Quantitative identification of slider nanoscale wear based on the head-disk interface dynamics

To reveal the mechanism of head-disk interface wear behaviors, this paper proposed a novel transformation on slider's vibration signals, which was derived to having a strong correlation with the slider wear. Based on the modal analysis, the high-frequency component was regarded as the air bearing mode while the low-frequency corresponds to the structure (suspension related) mode. Both structure and air bearing mode dissipated energies were extracted and the correlation analysis between the energy and wear volume verified the proportional relationship. Finally, regression analysis was employed to establish the linear model for wear and energy. This paper helps understand the wear mechanisms of slider from the interface dynamics response's view, and then provides a novel quantitative analysis approach for slider wear identification.

Modeling Strength Degradation of Fiber-Reinforced Ceramic-Matrix Composites Subjected to Cyclic Loading at Elevated Temperatures in Oxidative Environments

In this paper, the strength degradation of non-oxide and oxide/oxide fiber-reinforced ceramic-matrix composites (CMCs) subjected to cyclic loading at elevated temperatures in oxidative environments has been investigated. Considering damage mechanisms of matrix cracking, interface debonding, interface wear, interface oxidation and fibers fracture, the composite residual strength model has been established by combining the micro stress field of the damaged composites, the damage models, and the fracture criterion. The relationships between the composite residual strength, fatigue peak stress, interface debonding, fibers failure and cycle number have been established. The effects of peak stress level, initial and steady-state interface shear stress, fiber Weibull modulus and fiber strength, and testing temperature on the degradation of composite strength and fibers failure have been investigated. The evolution of residual strength versus cycle number curves of non-oxide and oxide/oxide CMCs under cyclic loading at elevated temperatures in oxidative environments have been predicted.

Modeling strength degradation of fiber-reinforced ceramic-matrix composites under cyclic loading at room and elevated temperatures

In this paper, the strength degradation of fiber-reinforced ceramic-matrix composites (CMCs) under cyclic loading at room and elevated temperatures has been investigated. The shear-lag model combined with the matrix statistical multiple cracking model, interface debonding criterion and fiber fracture model has been adopted to analyze the stress distributions in damaged CMCs, considering the damage mechanism of the interface wear. The relationships between the residual strength and peak stress, interface debonding, fiber failure and cycle number have been established. The effects of fatigue peak stress, initial and steady-state interface shear stress, fiber Weibull modulus and fiber strength on the degradation of residual strength and fibers failure have been investigated. The evolution of residual strength versus cycle number curves of fiber-reinforced CMCs under cyclic loading at room and elevated temperatures have been predicted.

Synergistic effects of temperature, oxidation, loading frequency and stress-rupture on damage evolution of cross-ply ceramic-matrix composites under cyclic fatigue loading at elevated temperatures in oxidizing atmosphere

In this paper, the synergistic effects of temperature, oxidation, loading frequency and stress-rupture on damage evolution of cross-ply ceramic-matrix composites (CMCs) under cyclic fatigue loading at elevated temperatures in oxidizing atmosphere have been investigated. The Budiansky-Hutchinson-Evans shear-lag model was used to describe the micro stress field of the damaged composite considering interface wear and interface oxidation. The damage parameters of fatigue hysteresis dissipated energy, fatigue hysteresis modulus, and fatigue peak strain have been used to monitor the damage evolution inside of CMCs. The relationships between damage parameters and internal damage of matrix cracking, interface debonding and slipping have been established. The experimental fatigue hysteresis, interface slip lengths and peak strain of cross-ply SiC/MAS composite under cyclic fatigue loading at different testing temperatures, loading frequency and stress-rupture time in air condition have been predicted.

Fatigue Life Prediction of 2D Woven Ceramic-Matrix Composites at Room and Elevated Temperatures

In this paper, the fatigue life of 2D woven ceramic-matrix composites, i.e., SiC/SiC, SiC/Si-N-C, SiC/Si-B4C, and Nextel 610™/Aluminosilicate, at room and elevated temperatures has been predicted using the micromechanics approach. An effective coefficient of the fiber volume fraction along the loading direction (ECFL) was introduced to describe the fiber architecture of preforms. The Budiansky-Hutchinson-Evans shear-lag model was used to describe the microstress field of the damaged composite considering fibers failure. The statistical matrix multicracking model and fracture mechanics interface debonding criterion were used to determine the matrix crack spacing and interface debonded length. The interface shear stress and fibers strength degradation model and oxidation region propagation model have been adopted to analyze the fatigue and oxidation effects on fatigue life of the composite, which is controlled by interface frictional slip and diffusion of oxygen gas through matrix multicrackings. Under cyclic fatigue loading, the fibers broken fraction was determined by combining the interface/fiber oxidation model, interface wear model and fibers statistical failure model at elevated temperatures, based on the assumption that the fiber strength is subjected to two-parameter Weibull distribution and the load carried by broken and intact fibers satisfy the Global Load Sharing (GLS) criterion. When the broken fibers fraction approaches to the critical value, the composites fatigue fractures. The fatigue life S-N curves of 2D SiC/SiC, SiC/Si-N-C, SiC/Si-B4C, and Nextel 610™/Aluminosilicate composites at room temperature and 800, 1000 and 1200 °C in air and steam have been predicted.

Synergistic Effects of Stress-Rupture and Cyclic Loading on Strain Response of Fiber-Reinforced Ceramic-Matrix Composites at Elevated Temperature in Oxidizing Atmosphere.

In this paper, the synergistic effects of stress rupture and cyclic loading on the strain response of fiber-reinforced ceramic-matrix composites (CMCs) at elevated temperature in air have been investigated. The stress-strain relationships considering interface wear and interface oxidation in the interface debonded region under stress rupture and cyclic loading have been developed to establish the relationship between the peak strain, the interface debonded length, the interface oxidation length and the interface slip lengths. The effects of the stress rupture time, stress levels, matrix crack spacing, fiber volume fraction and oxidation temperature on the peak strain and the interface slip lengths have been investigated. The experimental fatigue hysteresis loops, interface slip lengths, peak strain and interface oxidation length of cross-ply SiC/MAS (magnesium alumino-silicate, MAS) composite under cyclic fatigue and stress rupture at 566 and 1093 °C in air have been predicted.

Performance evaluation on high speed machining of custom 465 steel

Custom 465 steel is a martensitic, age-hardenable alloy having a superior combination of strength and corrosion cracking resistance, which are commonly used in aerospace industries. When machining Custom 465 steel, tool-work interface temperature and tool wear are the major parameters which influences the machinability factors at a greater extend. Even though, researchers have performed many operations based on this subject, no significant data’s were available regarding the Custom 465 steel.A dry machining operation known for its ecological desirable and cost effective process was implemented to experimentally investigate the tool wear and tool-work interface temperature when machining Custom 465 steel using uncoated, TiAlN and TiCN coated carbide cutting tool inserts with a cutting speed of 100 m/min and 200 m/min and also the effects of cutting speed on tool wear and tool-work interface temperature were also determined. The highest tool life of 6.15 minutes was recorded for TiAlN coated insert at a cutting speed of 2000 rotations per minute (rpm), feed rate of 200 mm/min and depth of cut of 0.5 mm. The maximum tool wear recorded for TiAlN coated insert was 0.25 mm and the maximum temperature on the tool-work impact was 142.43 degrees. In all cutting speeds, TiAlN coated insert outperformed uncoated and TiCN coated insert in term of tool life and temperature. For a cutting speed of 2000 rpm and above uncoated inserts are not suitable to be used for machining Custom 465 steel due to the rapid wear of cutting edge.

Synergistic Effects of Temperature, Oxidation and Multicracking Modes on Damage Evolution and Life Prediction of 2D Woven Ceramic-Matrix Composites under Tension-Tension Fatigue Loading

In this paper, the synergistic effects of temperature, oxidation and multicracking modes on damage evolution and life prediction in 2D woven ceramic-matrix composites (CMCs) have been investigated. The damage parameter of fatigue hysteresis dissipated energy and the interface shear stress were used to monitor the damage evolution inside of CMCs. Under cyclic fatigue loading, the fibers broken fraction was determined by combining the interface/fiber oxidation model, interface wear model and fibers statistical failure model at elevated temperature, based on the assumption that the fiber strength is subjected to two-parameter Weibull distribution and the load carried by broken and intact fibers satisfy the Global Load Sharing (GLS) criterion. When the broken fibers fraction approaches to the critical value, the composite fatigue fractures. The evolution of fatigue hysteresis dissipated energy, the interface shear stress and broken fibers fraction versus cycle number, and the fatigue life S–N curves of SiC/SiC at 1000, 1200 and 1300 °C in air and steam condition have been predicted. The synergistic effects of temperature, oxidation, fatigue peak stress, and multicracking modes on the evolution of interface shear stress and fatigue hysteresis dissipated energy versus cycle numbers curves have been analyzed.

The influence of surface properties on sliding contact temperature and friction for polyetheretherketone (PEEK)

Abstract Polyetheretherketone (PEEK) polymers are increasingly used in tribological applications. An important aspect of PEEK tribology is the surface temperature reached during sliding. At present, most knowledge of frictional heating in PEEK is based on post-hoc analysis of debris and wear surfaces. In this study, infrared thermography was used to observe the full field temperature map of PEEK against sapphire counterface during ball-on-disc sliding. The measured temperatures matched closely those predicted by flash temperature models. Additionally, friction studies were performed with steel and sapphire counterfaces. It was observed that PEEK debris readily deposited on steel but not on sapphire. The friction studies also indicated a greater adhesive friction response for PEEK against steel compared to PEEK against sapphire. The transfer of PEEK material to the steel surface may elevate the temperature at the sliding interface. Analysis of transfer films on steel suggests that the transferred PEEK was oriented in the direction of sliding. The deposition of debris and formation of oriented films resembled a high temperature drawing process, which was likely to be due to localized frictional heating. The results of this study illustrate the important role transfer films play in determining both the friction and temperature of the PEEK wear interface.

Interfacial debonding and slipping of carbon fiber-reinforced ceramic-matrix composites under two-stage cyclic loading

In this paper, the interface debonding and frictional slipping of carbon fiber-reinforced ceramic-matrix composites (CMCs) under two-stage cyclic fatigue loading have been investigated using micromechanics approach. Under cyclic fatigue loading, the fiber/matrix interface shear stress degrades with increasing cycle number due to interface wear. The synergistic effect of interface wear and fatigue loading sequence on interface debonding and frictional slipping has been analyzed. Based on the fatigue damage mechanism of fiber slipping relative to matrix, in the interface debonded region, upon unloading and subsequent reloading, the interface debonded length and interface slip lengths, i.e. interface counter-slip length and interface new-slip length, are determined using the fracture mechanics approach. The relationships between interface debonding, interface slipping, interface wear, cycle number, and different loading sequences are determined. There are two types of fatigue loading sequences considered, i.e. (1) cyclic loading under low peak stress for N1 cycles, and then high peak stress; and (2) cyclic loading under high peak stress for N1 cycles, and then low peak stress. The effects of peak stress level, interface wear, cycle number, and loading sequence on interface debonding and frictional slipping of fiber-reinforced CMCs have been analyzed. The fatigue hysteresis loops of cross-ply carbon fiber-reinforced silicon carbide composite corresponding to different cycle number under two-stage cyclic fatigue loading have been predicted.

Synergistic effect of interface wear and loading sequence on interface debonding and relative slipping of fiber-reinforced ceramic-matrix composites

This study investigates the synergistic effect of interface wear and loading sequence on interface debonding and relative slipping of fiber-reinforced ceramic-matrix composites (CMCs). There are five different fatigue loading sequences considered in the present analysis. Based on the fatigue damage mechanism of fiber slipping relative to the matrix upon unloading/reloading, the interface debonded length and interface slip lengths are determined using the fracture mechanics approach. The relationships between interface debonding, interface slipping, interface wear, cycle number, peak stress and loading sequence have been determined. The fatigue hysteresis loops of C/SiC composite under three-stage cyclic fatigue loading have been predicted using the present analysis.

In situ scratch testing and abrasion simulation of WC/Co

WC/Co hardmetals are used in many applications where wear resistance is important. However, despite recent work, the microstructural basis of wear is not completely understood.This paper describes the results of in situ scratch experiments carried out with a NPL designed and manufactured microtribometer in which spherically ended diamond indenters were moved under load across polished WC/Co samples to generate damage. The microtribometer was mounted in the chamber of a high resolution SEM so that sequential images and video of the damage generated by repeat scratches could be captured. In the experiments, the effects of changing the number of repeat passes, and whether repeat passes were carried out in the same lateral position over the top of the previous pass or with a random lateral offset to simulate abrasion were also investigated.The results gave valuable information on details of how the damage observed was related to the WC/Co microstructure. A major mechanism of damage, clearly observed in the videos of the damage accumulation appended with this paper, was the progressive fragmentation of WC grains; the movement of the WC fragments could be followed from one pass to the next until they are finally removed from the wear interface as debris.

Interfacial Debonding and Slipping of Carbon Fiber-Reinforced Ceramic-Matrix Composites Subjected to Different Fatigue Loading Sequences

AbstractIn this paper, the interface debonding and slipping of carbon fiber-reinforced ceramic-matrix composites (CMCs) subjected to different fatigue loading sequences have been investigated using the micromechanics approach. There are two different types of fatigue loading sequences considered: (1) cyclic loading under low peak stress for N1 cycles, and then high peak stress for N2 cycles; and (2) cyclic loading under high peak stress for N1 cycles, and then low peak stress for N2 cycles. Based on the fatigue damage mechanism of fiber slipping relative to matrix upon unloading/reloading, the interface debonded and slip lengths are determined by fracture mechanics approach. The relationships between interface debonding, interface slipping, interface wear, cycle number, fatigue peak stress, and fatigue loading sequence have been determined. The effects of peak stress level, interface wear, cycle number, and loading sequence on the interface debonding and slipping of fiber-reinforced CMCs have been analyze...

Comparison of Fatigue Life Between C/SiC and SiC/SiC Ceramic-Matrix Composites at Room and Elevated Temperatures

In this paper, the comparison of fatigue life between C/SiC and SiC/SiC ceramic-matrix composites (CMCs) at room and elevated temperatures has been investigated. An effective coefficient of the fiber volume fraction along the loading direction (ECFL) was introduced to describe the fiber architecture of preforms. Under cyclic fatigue loading, the fibers broken fraction was determined by combining the interface wear model and fibers statistical failure model at room temperature, and interface/fibers oxidation model, interface wear model and fibers statistical failure model at elevated temperatures in the oxidative environments. When the broken fibers fraction approaches to the critical value, the composites fatigue fracture. The fatigue life S–N curves and fatigue limits of cross-ply, 2D and 3D C/SiC and SiC/SiC composites at room temperature, 550 °C in air, 750 °C in dry and humid condition, 800 °C in air, 1000 °C in argon and air, 1100 °C, 1300 °C and 1500 °C in vacuum, have been predicted. At room temperature, the fatigue limit of 2D C/SiC composite with ECFL of 20 % lies between 0.78 and 0.8 tensile strength; and the fatigue limit of 2D SiC/SiC composite with ECFL of 20 % lies between 0.75 and 0.85 tensile strength. The fatigue limit of 2D C/SiC composite increases to 0.83 tensile strength with ECFL increasing from 20 to 22.5 %, and the fatigue limit of 3D C/SiC composite is 0.85 tensile strength with ECFL of 37 %. The fatigue performance of 2D SiC/SiC composite is better than that of 2D C/SiC composite at elevated temperatures in oxidative environment.