Wear Behavior Of Samples Research Articles

B4C reinforced NiTi‐based composites: Microstructure and wear performance

AbstractIn this study, NiTi–x wt.% B4C (x = 0, 2, and 4) composites were consolidated with spark plasma sintering method, and the effects of boron carbide reinforcement addition on the microstructure and wear behavior of samples were investigated. Identification of the constituent phases of samples by the X‐ray diffraction method plus Rietveld analysis revealed that the stability of the martensite phase increased in the composite samples because of mismatch stresses between the NiTi matrix phase and the reinforcing particles, which increases the density of the dislocations and facilitates the diffusion process that subsequently leads to the formation of stable intermetallics. The results of hardness test indicated that the hardness value increased from 3.67 GPa for pure NiTi to 10.99 GPa for NiTi–4 wt.% B4C. Results of wear test revealed that boron carbide reinforced composite specimens had higher wear resistance, whereas wear rate of NiTi sample was 3.6 × 10−3 mm3/N m, and it reached to .21 × 10−3 mm3/N m for NiTi–4 wt.% B4C. Investigation of microstructure by scanning electron microscopy images and EDS analysis revealed that the wear mechanism in NiTi samples was abrasive and the addition of B4C to NiTi changed the wear mechanisms from abrasive to a combination of oxidation, adhesive, and delamination mechanisms.

Effect on Microstructure and Mechanical Properties of Microwave-Assisted Sintered H13 Steel Powder with Different Vanadium Contents.

The present work demonstrated the first-ever preparation of block specimens by the microwave sintering of H13 alloy powder. Varying proportions of vanadium powder (1.5%, 2.5%, 3.5%, 4.5%, and 5.5% on a mass basis) were added to H13 mold steel and these mixtures were sintered using microwaves. X-ray fluorescence spectroscopy was employed to determine the compositions of the resulting specimens and vanadium percentages of 1.56%, 2.04%, 3.10%, 4.06%, and 4.20% were determined. These results demonstrate a clear trend, with significantly lower vanadium amounts than expected based on the nominal values at higher vanadium loadings. Different samples were also found to exhibit different degrees of ablation, and this effect was related to the presence of voids in the materials. The surface compositions of these specimens were examined by laser-induced breakdown spectroscopy and were found to be relatively uniform. The microstructures as well as the hardness properties of the materials were assessed. Microwave sintering of 100 g specimens at 1300 °C for 10-min generated samples with hardness values ranging from 205 HV (at the lowest vanadium content) to 175.2 HV (at the highest vanadium content). The wear behavior of samples prepared by microwave sintering H13 die steel with different vanadium contents at room temperature has been studied. The results showed that 1.5% vanadium content is the best mass ratio.

On the tribology of complex 2D/3D composites bearing

In the present work, a hierarchical braided polymer composite consists of Polytetrafluoroethylene (PTFE) fibers, reinforcement fibers, and epoxy resin was designed as a self-lubricant composite and bearing. Different reinforcements such as glass, carbon, and Kevlar fibers were employed to investigate the effect of reinforcement on the wear characteristics of composites. Besides, the influence of 2D/3D braid fabric was examined on the wear behavior of samples. Also, 90 and 120 N loads were applied to assess the load impact. Results illustrated that compared to glass and Kevlar, carbon could lead to a greater wear weight loss and friction coefficient. However, PTFE tribofilm was observed according to scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS) analysis. Moreover, with the increase of load, the wear stability of the composites faded significantly. Furthermore, the tribological features became inappropriate with the deployment of the 3D braid structure. Finally, the modeling of tribological parameters was carried out using response surface methodology-based D-optimal design. The adequacy of the models was checked by analysis of variance. Results implied that there is an excellent correlation between the model and the experiments.

Comprehensive study on quasi-static and dynamic mechanical properties and wear behavior of Mg—B4C composite compacted at several loading rates through powder metallurgy

The present study aims to fabricate and evaluate the mechanical properties and wear behavior of Mg metal matrix composite, reinforced by 0, 1.5, 3, 5 and 10 vol.% B 4 C microparticles. Mg—B 4 C samples were fabricated at 450 °C and under different loading rates by using split Hopkinson bar (SHB), drop hammer (DH) and Instron (QS) at strain rates of 1600, 800 and 0.008 s −1 , respectively. The mechanical properties including microhardness, quasi-static and dynamic compressive strengths and wear behavior of samples were experimentally investigated. The results show that, the hardness of SHB and DH samples is obtained to be 20.2% and 5.7% higher than that of the QS sample, respectively. The wear rate and wear mass loss of Mg−10.0%B 4 C samples fabricated by SHB were determined lower than those of the QS sample by nearly 33% and 39%, respectively. The quasi-static compressive strengths of Mg−5.0%B 4 C are improved by 39%, 30% and 29% for the SHB, DH and QS samples, respectively, in comparison with the case of pure Mg. Furthermore, it is discovered that the dynamic compressive strength of samples is 51%–110% higher than their quasi-static value with respect to the B 4 C content.

Microstructure and wear behavior of spherical NbC hardmetals with nickel-based binders on AISI 4145H steel

To investigate the effect of spherical NbC particles on the wear resistance of nickel-based coatings, five groups of samples were tested. The microstructure of nickel-based coatings reinforced by spherical NbC particles was examined through X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. The wear behavior of samples was analyzed by microhardness, coefficient of friction, 2D profile across the wear track and summary of tribological properties, respectively. The results shows that in the microstructure of nickel-based coatings reinforced by spherical NbC particles, γ-Ni solid solution and Cr23C6 dominated the coating, and complex carbides (NbC, Cr7C3 and a small amount of Cr3C2) and borides (Cr2B) were also detected. The hardness of the nickel-based coating was 400HV0.2. With the increase of the NbC content in the coating, the hardness gradually increased, reaching the maximum when the content was 40% NbC, which was 610HV0.2. The average friction coefficient of AISI 4145H steel was 0.473, and the average friction coefficient of nickel-based coating was 0.573. With the increase of NbC content in the coating, the friction coefficient of the coating gradually decreased, reaching the lowest at a NbC content of 40%, which was 0.470. Although the friction coefficient of the coating changed slightly with the addition of NbC, in the friction and wear of the nickel-based coating, the coating was adhesively worn, and there were many abrasive dust, scratches and grooves on the surface of the coating. By the way, there were only a few scratches on the surface after friction and wear of the nickel-based coating containing 40% NbC. The wear rate of the coating with 40% NbC content was about 1.6% of AISI 4145H steel or one-tenth of the nickel-based coating.

Wear behavior of pits textured grey cast iron rings with Zr/ZrN coatings under dry sliding

This study presents the influence of Zr/ZrN coatings on the tribological performance of pits textured grey cast iron parts under dry sliding. A laser marking system and a physical vapor deposition equipment were applied to manufacture pits textured grey cast iron rings combined with Zr/ZrN coatings. A pin-on-disc wear test rig was used to reveal the wear behavior of samples under dry wear condition, at a rotating speed of 200 r/min, with a normal load of 70 N. The wear losses and the worn surfaces of all rings were obtained by an electronic balance and a three-dimensional surface profilometer, respectively. The results show that Zr/ZrN coatings can significantly increase the surface roughness and surface hardness of grey cast iron rings. As a result, Zr/ZrN coatings increase the friction coefficients of all coated GCI rings, and reduce the wear losses of some ones. In this work, when surface texturing combines with Zr/ZrN coatings, the final tribological properties of coated grey cast iron rings may be either improved or deteriorated, depending on surface characteristics, texturing parameters and loads. Compared with the uncoated smooth grey cast iron ring, Zr/ZrN coatings cannot effectively improve the wear behavior of pits textured samples. Among all coated grey cast iron rings, when the diameter of the pit is 0.8 mm, and the distance between pits is 1.25 mm, the pits textured grey cast iron ring can provide the optimal anti-wear performance. This work would provide a valuable reference for the surface design of journal bearings and roller bearings.

Experimental investigation on mechanical properties and wear characterization of Al‐Si12CulMg1 aluminium alloy reinforced with titanium diboride and boron carbide particulate hybrid composites using stir casting process

AbstractLM13 aluminium alloy (Al−Si12CulMg1) with titanium diboride (TiB2) and boron carbide (B4C) particulate hybrid composites have been prepared using stir casting process. Wt% of titanium diboride is varied from 0–10 and constant 5 wt% boron carbide particles have been used to reinforce LM13 aluminium alloy. Microstructure of the composites has been investigated and mechanical properties viz., hardness, the tensile strength of composites have been analyzed. Wear behavior of samples has been tested using a pin on disc apparatus under varying load (20 N–50 N) for a sliding distance of 2000 m. Fracture and wear on the surface of samples have been investigated. Microstructures of composites show uniform dispersion of particles in LM13 aluminium alloy. Hardness and tensile strength of composites increased with increasing wt % of reinforcements. Dry sliding wear test results reveal that weight loss of composites increased with increasing load and sliding distance. Fracture on the surface of composites reveals that the initiation of crack is at the interface of the matrix and reinforcement whereas dimples are observed for LM13 aluminium alloy. Worn surface of composites shows fine grooves and delamination is observed for the matrix.

Investigation of dry sliding wear properties of multi-directional forged Mg–Zn alloys

Abstract Effect of multi-directional forging (MDF) on wear properties of Mg–Zn alloys (with 2, 4, and 6 wt% Zn) is investigated. Dry sliding wear test was performed using pin on disk machine on MDF processed and homogenized samples. Wear behavior of samples was analyzed at loads of 10 N and 20 N, with sliding distances of 2000 m and 4000 m, at a sliding velocity of 3 m/s. Microstructures of worn samples were observed under scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and x-ray diffraction (XRD) and the results were analyzed. Mechanical properties were evaluated using microhardness test. After 5 passes of MDF, the average grain size was found to be 30 ± 4 µm, 22 ± 3 µm, and 18 ± 3 µm, in Mg–2%Zn, Mg–4%Zn, and Mg–6%Zn alloys, respectively, with significant improvement in hardness in all cases. Wear resistance was improved after MDF processing, as well as, with increment in Zn content in Mg alloy. However, it decreased when the load and the sliding distance increased. Worn surface exhibited ploughing, delamination, plastic deformation, and wear debris along sliding direction, and abrasive wear was found to be the main mechanism.

Yüksek Fırın Cürufu Takviyeli Epoksi Kompozitin Kuru Kayma Davranışının İncelenmesi

Polymer matrix composites are advanced materials that can be used in a variety of applications such as low density, high strength, automobile, aerospace and home appliances. Common and commercially used composites generally use polymers as matrix materials and are commonly known as resin solutions. variety of polymer materials are available as matrix type and the commonly used matrix materials are epoxy, urethane, polyamide, polyester, polyether ether ketone (PEEK)… The reinforcement materials used are generally fibers, particles and ground minerals. Due to the increasing production of iron and steel, high levels of slag are emerging and pose problems for both producers and the environment. From this point of view, in this study, it has been investigated on the wear behavior of the epoxy matrix as a reinforcement in order to evaluate the blast furnace slag (BFS), which is known to have hard ceramic components. EP100 epoxy resin and EP385H hardener are commercially available. The epoxy resin was selected as matrix and Al 2 O 3 and blast furnace slag dusts of 61 µm, 91 µm and 125 µm were used as reinforcement (Table 1). In the produced composites the reinforcement ratio was kept constant at 30% and the epoxy and reinforcement powders were mixed until a homogeneous mixture was obtained. The curing agent was added during the mixture and at the end of the process the mixture was poured into the silicone mold. The samples were then allowed to cure for 36 hours at room temperature. Dry sliding wear behavior of samples tested with ball on disc wear device. The wear resistance of the composites reinforced with blast furnace slag at all conditions was higher than the samples reinforced with Al 2 O 3 . However, the volume losses of composites reinforced with blast furnace slag especially at low loads are much lower than the samples reinforced with Al 2 O 3 . The reason for this; It can be shown that the blast furnace slag having a fragile structure is broken under high load and divided into many sharp edges and these particles contribute to abrasion by acting as abrasive material in front of the abrasive ball. The volume losses of the samples increased with increasing load. Because the two forces during wear affect the wear losses. One of them is the force acting on the counter-surface of the ball, while the other is the shear force. The increase of the load increased the penetration of abrasive ball to the opposite surface. Therefore, the amount of material to be affected during the relative movement of the abrasive ball is also increased. As a result, if sufficient shear force occurs, it transfers more mass from the ball to the surface. In both types of composite, increased reinforcement particle size resulted in increased wear losses. Low size reinforcement particles are more homogeneously distributed in the matrix at more points. In this case abrasive ball will be more difficult to penetrate into the matrix and will contribute more to the wear resistance of the low-dimensional particle reinforced composite material. In addition, low-dimensional particles will have more adhesion in the matrix. This will help reduce wear losses. Both Al 2 O 3 and blast furnace slag reinforced composites showed fatigue related surface deterioration and plastic deformation wear mechanisms. However, plastic deformation was the predominant wear mechanism in blast furnace slag reinforced composites, while Al 2 O 3 reinforced composites were predominantly identified as a fatigue-related surface damage wear mechanism.

Influence of aging, varying particle size & volume fraction of Al2O3 particles on the hardness and wear behavior of Al 7150 alloy composite produced by hot uniaxial compaction method

The influence of aging, particle size and volume fraction (5, 10, 20 & 25%) of alumina particulates on the hardness & wear behavior of Al 7150 alloy composites produced by hot uniaxial compaction method was investigated. The as-received Al2O3 particulates were first mechanically ball milled for durations of 45, 180, 360, 420 and 580 min to reduce its particle size. The milled alumina particles of 165 nm, 65 nm, 45 nm, 27 nm and 21 nm were later independently blended with the Al 7150 alloy powders to produce five sets of cylindrical specimens using a punch-die setup. The compaction pressure was 500 MPa with a holding time of 3 h, at a temperature of 400 °C. The Vickers microhardness tests revealed an improvement in the hardness with the increase in the volume % of the reinforcement and decreasing particulate size. The Age hardenability of the composites was also investigated by first solutionizing the composite samples followed by aging at 3 h (T4-underage), 24 h (T6-peak age) & 96 h (T7-overage). The wear behavior of the samples was studied by comparing the wear rate of the un-reinforced alloy and non-heat treated (reinforced) Al 7150 alloy composite samples with T6 heat treated composite specimens using a pin on disc wear testing machine under different load and sliding distance conditions. The test specimens were characterized using XRD, FESEM and EDS analysis. Apart from the effect of particle size and volume fraction of Al2O3 reinforcement, the precipitation hardening which occurred during aging, influenced the microhardness and wear behavior of the composite samples.

Tribological properties of B4C reinforced aluminum composite coating produced by TIG re-melting of flame sprayed Al-Mg-B4C powder

Producing a high-performance surface composite layer under severe tribological conditions such as wear was main purpose of this investigation. In this regard, B4C submicron-sized particles were chosen as reinforcement to increase tribological properties of Al-Mg alloy. A surface layer with a mixture of Al and B4C powders (5 wt%B4C) was made using thermal spray process on the substrate and then melted using gas tungsten arc welding (GTAW) technique to produce composite coating. Microstructure, formed phases and reinforcement particles in the composite layer were examined, as well. Wear behavior of samples against steel disc with hardness of 62 HRC was evaluated by a pin-on-disk setup of experiment at ambient temperature. The results illustrated significant reduction in the friction coefficient and weight loss; around 35 and 60% in comparison with uncoated substrate, respectively and showed a decline in wear rate up to 48%. Moreover, a substantial increase, up to 4 times, in the hardness of Al/5 wt%B4C composite coating was observed compared to the original substrate.

The Wear of Glass Fiber Reinforced Polyester Composite Materials at Different Loads and Speeds

Glass fiber reinforced polyester (GFRP) materials which are polymer matrix composites have some properties such as high specific strength, excellent elasticity, low weight, high corrosion resistance, high chemical resistance and high thermal stability. One of most important causes of failure of mechanical parts is wear. It is a surface property that can be reduced by changing the surface chemistries of the materials and microstructures. For this reason GFRP materials should be investigated not only for their mechanical properties but also for their tribological behaviours. The aim of this study is investigation of effects of different fillers and resins materials on adhesive wear properties of GFRP at different loads and speeds. In the sample production, different resins (reactive orthophtalic polyesters), reinforcing materials and fillers (glass beads, alumina) are used. . Initially, the samples were subjected to adhesive wear tests on two different loads (F=10N, F=20N) and two different speeds (n=100rpm, n=200rpm) at 150m sliding distance. The friction force and friction coefficient were measured during the test on tribometer. The densities of samples were measured. In the next step, the wear trace thicknesses were measured and the wear rates were calculated. In results, the addition of glass beads to plain orthophtalic polyester resin reduced wear rate. The influence of load effect on wear behavior of samples is more the influence of speed.

Investigating the effect of holding duration at a deep cryogenic temperature on the wear behavior of DIN 1.2080 (D3) tool steel

This work focused on the effect of the holding time in a deep cryogenic heat treatment on the wear behavior, microstructural changes, retained austenite percentage and microhardness of 1.2080(D3) tool steel. These analyses were performed via optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and energy dispersion spectroscopy (EDS) to study the microstructure. A pin-on-disk wear testing machine was employed to investigate the wear behavior. The microhardness changes were measured by KOPA machine. It was shown that the deep cryogenic heat treatment eliminates retained austenite and makes a more uniform carbide distribution with higher percentages. Furthermore, some new nano-sized carbides form during the deep cryogenic treatment, thereby increasing the hardness and improving the wear behavior of the samples. It was also observed that the deep cryogenic heat treatment improves the wear behavior and microhardness of samples with an increase in the holding duration up to an optimum value: beyond that duration, the wear resistance and microhardness decreases to a specific value, and changed specifically at longer holding durations. It was also observed that the predominant wear mechanism was a combination of adhesive and tribochemical wear.

Effect of active screen plasma nitriding pretreatment on wear behavior of TiN coating deposited by PACVD technique

Titanium based alloys are used extensively for improving wear properties of different parts due to their high hardness contents. Titanium nitride (TiN) is among these coatings which can be deposited on surface using various techniques such as CVD, PVD and PACVD. Their weak interface with substrate is one major drawback which can increase the total wear in spite of favorite wear behavior of TiN. Disc shaped samples from AISI H13 (DIN 1.2344) steel were prepared in this study. Single TiN coating was deposited on some of them while others have experienced a TiN deposition by active screen plasma nitriding (ASPN). Hardness at the surface and depth of samples was measured through Vickers micro hardness test which revealed 1810Hv hardness as the maximum values for a dual-layered ASPN–TiN. Pin-on-disc wear test was done in order to study the wear mechanism. In this regard, the wear behavior of samples was investigated against pins from 100Cr6 (Din 1.3505) bearing steel and tungsten carbide–cobalt (WC–Co) steel. It was evidenced that the dual-layer ASPN–TiN coating has shown the least weight loss with the best wearing behavior because of its high hardness values, stable interface and acceptable resistance against peeling during wearing period.

Development in Wear Resistance of Fe-0.7Cr-0.8Mn Milling Balls through <i>In Situ</i> Reinforcing with Low Weight Percent TiC

In order to increase wear resistance of Fe-0.7Cr-0.8Mn cold work tool steels, low weight percentage of Ti incorporated to the alloy and subsequently, because of high affinity between additive titanium and carbon content in this alloy, low weight percentage of TiC in situ formed in matrix. These composites can be used as the milling balls in mining and cement industries because of their improved wear resistance. Formation, shape, size and distribution of TiC particles within the matrix were studied by optical microscopy equipped with image analyzer, optical emission spectroscopy, scanning electron microscopy and energy dispersive spectroscopy. Also microhardness and density of the samples measured. Abrasion wear tests were carried out using a pin on disc type machine. An experimental design based on Taguchi method was applied to investigate the effect of TiC content, applied load, sliding distance and roughness of SiC abrasive paper on wear behavior of samples. The results show that by reinforcing the Fe-0.7Cr-0.8Mn steels with low weight percentage of TiC, wear resistance of these kind of milling balls significantly increases. Sliding distance has the most influence on wear rate of samples, also weight loss of samples decreases as sliding distance, applied load and roughness of grinding decreases.

Effects of Temperature and Load on Wear for Different Matrix and Fibre-Reinforced Composite Materials

In this study, wear behaviours of fiber-reinforced and matrix composite materials are experimentally investigated under different speeds, loads and temperature. Composite materials were made of Kevlar-epoxy resin, glass fibre-epoxy resin and glass fibre -polyester resin materials. Tests were conducted for speeds of 0.390 and 0.557 m/s at two different loads of 5N and 10N respectively. Wear in the experiments was determined as lost in mass.In addition, the wear behaviour of samples was investigated through the SEM observation.

Effects of different metals on adhesive wear behaviour of alloy surface produced by TIG process

Low carbon steel surfaces were alloyed with composite powders using the tungsten inert gas welding method. After the alloying process, the effects of cladding surface on the microstructural characteristics and adhesive wear of the alloyed samples were examined. The sliding wear behavior of samples was investigated in a block on ring apparatus under the loads of 20, 40, 60 and 80 N respectively. In the experimental investigation, a low carbon steel surface was alloyed with austenitic stainless steel powder and austenitic stainless steel powder mixed with 4·5% Co, Mo and Ti particles respectively. Following surface alloying, conventional characterisation techniques, such as optical microscopy, scanning electron microscopy, energy dispersive spectrograph and X-ray diffraction, were used to study the microstructure of the alloyed zone. Examination of the microstructure revealed the presence of M23C6 carbides, solid melt phases and intermetallic phases, such as Ni3Ti, depending on the alloying element in the composite. As the amount of the reinforcing material increased, the saturation rates for the samples decreased, while their hardness increased. The adhesive abrasion tests conducted revealed that temperature input plays a significant role on the microstructure characteristics, which positively affected the adhesive abrasion values of the samples. Consequently, the tungsten inert gas welding method was successfully used for the surface alloying of low carbon steels.

Erosive–corrosive wear behaviour of Fe–TiC and cobalt based layers separately deposited on En31 steel

Observations pertaining to the erosive–corrosive wear behaviour of samples of En31 steel hardfaced separately with Fe–TiC and a commercial cobalt based material are reported in the present investigation. Erosion–corrosion tests were carried out by the sample rotation technique in 3·5%NaCl solution for varying test durations of 8–32 h (corresponding traversal distances 136–544 km) at a fixed traversal speed of 4·71 m s−1. The effect of the hardfaced layer on the wear behaviour was assessed through testing one set of each of the hardfaced and substrate steel samples under identical test conditions. The wear rate increased initially with traversal distance, attained the maximum and decreased thereafter. In the case of the steel substrate, the wear rate increased once again towards the final stage of testing. Hardfaced layers exhibited substantially decreasing wear rate compared with the substrate. Moreover, the performance of the Fe–TiC composite layer was intermediate between those of the cobalt based hardfacing material and the substrate. The observed response of the samples has been substantiated through their affected surface and subsurface characteristics.