T. Tsukizoe

The effect of slip amplitude on fretting

Abstract The effect of slip amplitude on the mechanism of fretting was investigated. Measurements of wear volume, frictional coefficient and of electrical contact resistance were carried out to clarify the wear mechanism. X-ray microdiffraction was used to observe the difference of wear behaviour, and scanning electron microscopic observations were made. At small slip amplitudes wear damage was small compared with that at larger amplitudes the transition being in the region of 70 μ. At smaller slip amplitudes fretting oxidation, a mild type of wear occurs. At larger slip amplitudes, adhesion and abrasion together with oxidation cause fretting wear. At much larger slip amplitudes, wear similar to reciprocating sliding wear occurs.

Chapter 7 - Friction and Wear Performance of Unidirectionally Oriented Glass, Carbon, Aramid and Stainless Steel Fiber-Reinforced Plastics

Abstract Friction and wear of unidirectionally oriented fiber-reinforced plastics (FRP) against mild steel have been investigated. The law of mixtures in the calculation of the friction coefficient of FRP is deduced, and the validity of this law is discussed by a comparison of computed values with experimental data. The wear performances of seven different kinds of FRP are summarized. A model for wear of FRP is proposed stating that the wear proceeds by wear-thinning of the fiber reinforcements, subsequent breakdown of the fibers and by peeling off of the fibers from the matrix. Based on this model, the wear equation for FRP is also proposed. Seizure of FRP as well as friction and wear of hybrid FRP, SiC-FRP and mica dispersion-reinforced polyester resin are also described. The finite element method was applied to stress analysis of FRP under friction processes. The principal stress distributions at the FRP surface and around the fiber reinforcement were computer-simulated.

Characteristics of fretting of carbon fibre reinforced plastics

Abstract Fretting between carbon fibre reinforced plastics (CFRP) and mild steel was investigated. The wearing properties are significantly affected by the direction of sliding. This phenomenon regarded as a tribological anisotropy of CFRP fretting is dependent upon carbon fibre resistance to reciprocating sliding. The best resistance against fretting was found when the steel specimen slid in a direction parallel to the unidirectionally oriented carbon fibres, and within a region about 30° from the carbon fibre axis.

Ion‐beam plating using mass‐analyzed ions

An ion‐beam‐plating apparatus controlled by mass spectrometry was developed to study the fundamentals of ion plating. A decelerating lens system was fitted to the apparatus and the deposition was carried out at ion energies from 30 to 300 eV. By the elimination of contaminant ions and neutrals and making the kinetic energy of incident ion‐beam constant the fundamental deposition mechanism can be discussed. A high‐voltage transmission electron microscope at 2000 kV was employed for examining ion‐beam‐induced dislocations in single‐crystal substrates of aluminum and the growth of ion‐beam‐plated films. The effects of kinetic energy and substrate orientation are discussed. It was found that the higher the ion energy, the higher the dislocation density. A high density of dislocation was observed on the close‐packed plane, i.e., (111) of an aluminum single crystal. Stainless steel was also used as a substrate. In this case, a twin deformation was found. The high‐voltage transmission electron microscope provide...

On the microscopic processes involved in metallic friction

Abstract A high–voltage transmission electron microscope (TEM) has been used to investigate the mechanism of friction. A single–pass sliding in air, the moat fundamental test system in tribology, was conducted using a copper single crystal. It was found that the greater the degree of deformation, the larger the friction coefficient; friction is thus primarily a resistance of deformation during sliding. A further TEM study on the cross-sections of a friction track clarified the microscopic constitution of the work-hardened layer to contain a texture, a distorted region, a compressed zone and an undisturbed matrix.

Friction and prow formation in a scratch process of copper by a diamond cone

Abstract A deformation process of flat copper surfaces scratched by diamond conical riders was observed by a metallographic technique and scanning electron microscopy. The geometric shape and the size of prows formed by material pile-up in front of the rider were examined and their influence on friction was investigated. It was found that, taking into account the actual shape of the prow, the friction force can be obtained theoretically for any cone angle.

Effects of distribution of surface slopes and flow pressures of contact asperities on contact between solid surfaces

Abstract An analysis of the mechanism of contact between two solids was carried out considering the distribution of the surface slopes of conical asperities and the variation of the flow pressure of each contact asperity due to work-hardening and the work-hardened layer of the softer surface. From the analysis, where the distributions of the surface heights and the surface slopes are Gaussian the number of contact points decreases and their mean radius increases with increasing ranges of the distribution of the surface slopes for a given value of the mean surface slope. The number of contact points, the total real area, the separation and the radius of the contact points are influenced by the variation of the flow pressure of each contact asperity due to work-hardening of the contact asperities or the work-hardened layer of the softer surface. The validity of the theory was checked by comparing the theoretical and experimental results of the number, the separation and the distribution of the radii of contact points.

Analysis of a wear process using the finite element method

Abstract The wear process of pure aluminum was studied using a finite element elastic-plastic analytical computer program. Yielding of the material initiated by sliding and a heavily deformed region originated below the surface. Void nucleation and crack propagation were simulated with a large-scale computer. Wear sheet formation of the type proposed by Suh was observed. The differences between adhesive wear and delamination wear are discussed in terms of the results of the finite element method calculations.

Prevention of fretting by ion plated film

Abstract A new technological application of the ion plating technique to the prevention of fretting has been studied. Ion plating was done using gold and silver, which are commonly employed as thin metal film lubricants and also boron carbide which has extremely good wear resistance. The anti-fretting property of the ion plated film was always superior to that of the sputtered or vacuum evaporated film. The ion plated boron carbide film showed the best resistance to fretting. The better adhesion of ion plated films was responsible for the better anti-wear property. Transmission electron microscopy was used to study ion plated films.

Metal transfer in the frictional contact of a rough hard surface

Abstract The frictional behaviour between a hard rough surface and a soft smooth surface was examined under lubricated and unlubricated conditions. Transfer of soft metal to hard asperities in contact with it caused significant changes in the shape, size and height distributions of the asperities. Thus metal transfer reduced the effect of the initial surface roughness of the hard metal on friction.