Prediction of cavitation wear resistance of metallic materials based on the results of measuring the roughness of a worn surface

2021 ◽  
pp. 22-29
Author(s):  
Keyword(s):  
Surface Roughness ◽  
Wear Resistance ◽  
Incubation Period ◽  
Fresh Water ◽  
Metallic Materials ◽  
Relative Wear Resistance ◽  
Rate Of Increase ◽  
Incubation Periods ◽  
Cavitation Wear ◽  
Worn Surface

A method is proposed for predicting the relative cavitation wear resistance of metallic materials using the ratio of the durations of their incubation periods of wear, based on measuring the rate of increase in surface roughness during the incubation period. The experiments were carried out in fresh water and artificial seawater. Keywords: cavitation wear, metal alloy, relative wear resistance, incubation period, surface roughness. [email protected]

scholarly journals Effects of Microstructure Evolution on Fretting Wear Behaviors of 25CrNi2MoVE Steel under Different Tempering States

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 351
Author(s):  
Xiongfeng Hu ◽  
Fuqiang Lai ◽  
Shengguan Qu ◽  
Yalong Zhang ◽  
Haipeng Liu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Wear Resistance ◽  
Wear Rate ◽  
Wear Mechanisms ◽  
Adhesive Wear ◽  
Operating Conditions ◽  
Fretting Wear ◽  
Fatigue Wear ◽  
Tempering Temperature ◽  
Worn Surface

Increasing load requirements and harsh operating conditions have worsened the wear of drive shafts in special field vehicles. In this paper, the evolution of the microstructure and fretting wear behaviors of 25CrNi2MoVE torsion shaft steel and their influence on the wear mechanisms were investigated as a function of tempering temperature. The results showed that the coarse grain size, low matrix hardness and non-metallic inclusions in the as-received state lead to a high wear rate and serious adhesive wear. The grain refinement after normalizing and the formed M5C2 carbide and bainite helped to improve the wear resistance and worn surface quality. Low temperature tempering is conducive to further improve the wear resistance of normalized samples, and the wear rate and worn surface roughness are increased gradually after tempering temperature increases. For quenching, although martensite structure can achieve a lower wear rate, the coefficient of friction is much higher; the wear mechanisms are primarily fatigue wear and adhesive wear. Although the adhesive wear degree and worn surface roughness were increased, the optimal anti-wear performances are obtained under tempering at 350 °C with good continuity of the surface oxide film. Excessive tempering temperature will make the softened matrix unable to form a beneficial “third-body wear”.

scholarly journals The behaviour of composites, glass ionomers and compomers in erosive conditions – in vitro study

2014 ◽  
Vol 60 (5) ◽  
pp. 200-203
Author(s):  
Andreea Borş ◽  
Cristina Molnar-Varlam ◽  
Melinda Székely
Keyword(s):  
Surface Roughness ◽  
Wear Resistance ◽  
Erosive Wear ◽  
In Vitro Study ◽  
Vitro Study ◽  
Initial Surface ◽  
Dental Filling ◽  
Filling Materials ◽  
Restorative Materials

Abstract Objective: The aim of this in vitro study was to evaluate the influence of erosive conditions on the wear resistance of aesthetic direct restorative materials. Methods: Six dental filling materials were tested: two composites (Filtek Z550 and X-tra fil), two compomers (Dyract Extra and Twinky Star) and two glass ionomers (Ketac Molar and Fuji II LC). Twenty disks (10mm×2mm) of each material were prepared (n=120) and kept in artificial saliva at 37˚C for 24 hours. Specimens were cycled in acidic soft drink (Coca-Cola) 5×/day, for 5’, over 30 days. Initial surface roughness ISR (Ra-μm) and final surface roughness FSR were measured using a profilometer. The wear rate was calculated as difference of final minus the initial roughness (ΔSR=FSR-ISR). For statistical analysis t-test and one-way ANOVA test were used by GraphPad Prism version 5.03 statistical software. The level of significance was set at p<0.05. Results: The erosive wear rates (mean±SD, μm) after exposure to acidic beverage were: 0.30±0.03 (Ketac Molar), 0.28±0.04 (Fuji II LC), 0.27±0.00 (Filtek Z550), 0.23±0.01 (X-tra fil), 0.20±0.00 (Twinky Star) and 0.14±0.01 Dyract Extra, respectively. There were significant differences between the tested materials (p<0.05). Conclusions: Dental filling materials had different behaviour under the same erosive condition, however all investigated aesthetic restorative materials showed surface degradation. These findings suggest that erosive wear resistance of tooth coloured restoratives could influence their longevity in intraoral acidic conditions. Acknowledgements: The study was supported by the Internal Research Grant no. 5/30.01.2013 of the University of Medicine and Pharmacy of Tirgu Mureş.

scholarly journals Preliminary In Vitro Wear Assessment of Ceramic Cemented Femoral Components Coupled with Polyethylene Menisci

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2112
Author(s):  
Saverio Affatato ◽  
Paolo Erani ◽  
Maurizio Fersini ◽  
Vincenzo Contaldi ◽  
Anna Rita Terrizzi ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Wear Resistance ◽  
Monoclinic Phase ◽  
Calf Serum ◽  
Wear Test ◽  
Clinical Test ◽  
Preliminary Evaluation ◽  
Before And After ◽  
Roughness Measurements

Success of total knee replacement (TKR) depends on the prosthetic design and materials. The use of metal components is well established with the disadvantage of allergic reactions. Ceramics have been recently proposed because of high wear resistance, excellent biocompatibility, wettability, and suitable mechanical properties. This study was aimed at investigating in vitro wear resistance of Zirconia Toughened Alumina (ZTA)/Ultra-high-molecular-weight polyethylene (UHMWPE) of TKR femoral components. An in vitro protocol was designed with the application of relevant load profile, 6-degrees-of-freedom knee simulator, and 8 × 105 cycles on the ZTA/UHMWPE configuration under bovine calf serum. Before and after wear test, the femoral components were investigated by using the Scanning Electron Microscope (SEM) and the X-Ray Diffraction (XRD) analyses, and stylus surface roughness measurements. The proposed pre-clinical test yielded repeatable results. In particular, gravimetric results showed that, after 8 × 105 cycles, the mean weight loss of the polyethylene mobile components is 5.3 ± 1.1 mg. The surface roughness measurements (Ramax) performed after the wear test showed no significant variation on the UHMWPE menisci. A slight increase of roughness has been found on the ZTA (0.02 µm before wear test, 0.28 µm after the test). SEM observations did not show significant modification of the surface morphology. Tetragonal to monoclinic phase ratio was measured by XRD before and after wear test to evaluate stability of tetragonal ZrO2 phase. Minimal conversion of tetragonal to monoclinic phase was found from 5.4 to 8%. Although this study is a preliminary evaluation limited to in vitro tests, it provides novel pre-clinical indications about the potential of ceramic TKR femoral components.

Enhancement of tribological properties and characteristic of polymer matrix composite (UHMWPE reinforced with short fibres of polyester) for Total Disc Replacement (TDR)

2020 ◽  
Vol 2 (102) ◽  
pp. 55-65
Author(s):  
M.N. Obaid ◽  
S.H. Radhi
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Wear Resistance ◽  
Composite Material ◽  
Thermal Properties ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Total Disc Replacement ◽  
Short Fibres ◽  
The Matrix

Purpose: The number of people suffering from Degenerative Disc Disease (DDD) is increasing. The disease causes heavy pain and restrict a number of day-to-day life activities. In extreme cases, the degraded disc is removed under total disc replacement which is usually made up of Ultra-High Molecular Weight Polyethylene (UHMWPE). The material has astounding biocompatible characteristics mechanical properties and wear resistance. However, these characteristics are insufficient in arthroplasty application. Therefore, research investigations are ongoing to improve tribological properties through reinforcement that may result in a composite material of UHMWPE. Thus the current study is aimed at reinforcing UHMWPE with short fibres of polyesters to enhance the tribological properties and surface characteristic so as to improve wear resistance and nourish the fibroblast cells on synthetic disc. Design/methodology/approach: The researcher prepared UHMWPE composite material, reinforced with different weight fractions of short polyester fibres (2, 4, 6, 8 and 10% following hot press method. Further pin-on-disc device was used to study the tribological properties (coefficient of friction and volume of wear). The study tested surface roughness and surface characteristics by atomic force microscopy (AFM) device, hardness by shore D device, contact angle to study the effect of polyester short fibres on wettability of UHMWPE surface and tested the thermal properties and crystalline degree using Differential Scanning Calorimetry measurement (DSC) device. Findings: The results infer that the wear resistance got improved when using 2% w.t polyester though it got decreased initially. However, the value was still more than neat UHMWPE. There was a decrease observed in coefficient of friction, but after 4 w.t% polyester, the coefficient of friction got increased due to increasing percentage of fibres which make it harder and stiff compared to UHMWPE. There was a decline observed in surface roughness due to alignment of the fibres with smooth surface. The contact angle got increased in a moderate range while the roughness enhanced the growth of fibroblast cell. The hardness of composite material got increased, because the fibres turned stiffer and harder than the matrix. DSC results infer the improvements in thermal stability due to high thermal properties of polyester fibres compared to UHMWPE. The degree of crystallinity got increased which in turn enhanced wear resistance, especially at 6 w.t % polyester fibres. There was a mild increase observed in density since the density of polyester is higher than polymer. Research limitations/implications: The major challenge was the dispersion of fibres. Uniform distribution of fibres within the matrix (UHMWPE) was achieved through two steps of mixing processes such as mechanical mixture and twin extruder. In future studies, fatigue tests must be conducted to study the behaviour of prepared composite materials under fatigue cycle. Practical implications: A significant objective is how to connect among different properties to obtain good improvement in tribological and surface properties so as to enhance wear resistance and growth of fibrolase cells. Originality/value: In this study, polymeric short fibres were used as reinforcement with polymeric matrix to enhance the wettability of fibres with matrix. In this way, the bonding among them got increased which supports the tribological, surface, and crystalline behaviour.

Performance characteristics of steel 1.2842 after nitridation

2021 ◽  
Vol 16 (1) ◽  
pp. 43-48
Author(s):  
Michal Krbaťa ◽  
◽  
Jana Escherová ◽  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Wear Resistance ◽  
Chemical Composition ◽  
Plasma Nitriding ◽  
Cutting Tools ◽  
Operating Costs ◽  
Mechanical And Tribological Properties ◽  
Structure Thickness ◽  
Pin On Disc

The paper deals with the change in mechanical properties and wear of 1.2842 universal tool steel after plasma nitriding, which is widely used to produce cutting tools with good durability and low operating costs. Plasma nitriding was performed at a temperature of 500 °C for 10-hour period in a standard N2 /H2 atmosphere with 1:3 gases ratio. Microstructure, phase structure, thickness of a nitriding layer and surface roughness of samples were measured with optical microscopes and a profilometer. Verification of a chemical composition was carried out on the BAS TASMAN Q4 device. Wear resistance was measured on a universal TRIBOLAB UTM 3 tribometer, through a, “pin on disc“ method. The results of experiments have shown that plasma nitriding process, significantly improves the mechanical and tribological properties of selected materials.

Erosion characteristics on surface texture of additively manufactured AlSi10Mg alloy in SiO2 quartz added slurry environment

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Recep Demirsöz ◽  
Mehmet Erdl Korkmaz ◽  
Munish Kumar Gupta ◽  
Alberto Garcia Collado ◽  
Grzegorz M. Krolczyk
Keyword(s):  
Surface Roughness ◽  
Weight Loss ◽  
Wear Resistance ◽  
Erosive Wear ◽  
Oxide Ceramics ◽  
Slurry Erosion ◽  
Content Type ◽  
Test Setup ◽  
Quartz Sands ◽  
Erosion Test

Purpose The main purpose of this work is to explore the erosion wear characteristics of additively manufactured aluminium alloy. Additive manufacturing (AM), also known as three-dimensional (3D) manufacturing, is the process of manufacturing a part designed in a computer environment using different types of materials such as plastic, ceramic, metal or composite. Similar to other materials, aluminum alloys are also exposed to various wear types during operation. Production efficiency needs to be aware of its reactions to wearing mechanisms. Design/methodology/approach In this study, quartz sands (SiO2) assisted with oxide ceramics were used in the slurry erosion test setup and its abrasiveness on the AlSi10Mg aluminum alloy material produced by the 3D printer as selective laser melting (SLM) technology was investigated. Quartz was sieved with an average particle size of 302.5 µm, and a slurry environment containing 5, 10 and 15% quartz by weight was prepared. The experiments were carried out at the velocity of 1.88 (250 rpm), 3.76 (500 rpm) and 5.64 m/s (750 rpm) and the impact angles 15, 45 and 75°. Findings With these experimental studies, it has been determined that the abrasiveness of quartz sand prepared in certain particle sizes is directly related to the particle concentration and particle speed, and that the wear increases with the increase of the concentration and rotational speed. Also, the variation of weight loss and surface roughness of the alloy was investigated after different wear conditions. Surface roughness values at 750 rpm speed, 10% concentration and 75° impingement angle are 0.32 and 0.38 µm for 0 and 90° samples, respectively, with a difference of approximately 18%. Moreover, concerning a sample produced at 0°, the weight loss at 250 rpm at 10% concentration and 45° particle impact angle is 32.8 mg, while the weight loss at 500 rpm 44.4 mg, and weight loss at 750 rpm is 104 mg. Besides, the morphological structures of eroded surfaces were examined using the scanning electron microscope to understand the wear mechanisms. Originality/value The researchers verified that this specific coating condition increases the slurry wear resistance of the mentioned steel. There are many studies about slurry wear tests; however, there is no study in the literature about the quartz sand (SiO2) assisted slurry-erosive wear of AlSi10Mg alloy produced with AM by using SLM technology. This study is needed to fill this gap in the literature and to examine the erosive wear capability of this current material in different environments. The novelty of the study is the use of SiO2 quartz sands assisted by oxide ceramics in different concentrations for the slurry erosion test setup and the investigations on erosive wear resistance of AlSi10Mg alloy manufactured by AM.

INFLUENCE OF THE DYNAMICS OF FORCED MOTION ON THE STATIC FRICTION IN METAL-POLYMER SLIDING PAIRS

Tribologia ◽  
2021 ◽  
Vol 295 (1) ◽  
pp. 21-26
Author(s):  
Mariusz Opałka ◽  
Wojciech Wieleba ◽  
Angelika Radzińska
Keyword(s):  
Relative Motion ◽  
Friction Pair ◽  
Polymeric Materials ◽  
Static Friction ◽  
Metallic Materials ◽  
Test Results ◽  
Friction Resistance ◽  
Rate Of Increase ◽  
Polymer Metal ◽  
Metal Polymer

The resistance during the frictional interaction of polymeric materials with metallic materials is characterized by a significant dependence on the dynamics of the motion inputs. In a metal-polymer friction pair, the static friction resistance during standstill under load depends on the rate of growth of the force causing the relative motion. Tribological tests of selected (polymer-metal) sliding pairs were carried out. The selected polymers were polyurethane (TPU), polysulfone (PSU), and silicone rubber (SI). They interacted with a pin made of normalized C45 steel under unitary pressure p = 0.5 MPa in dry friction conditions at different gradients of the force driving the relative motion (dF/dt = 0.1-20 [N/s]). The static friction coefficient of the selected sliding pairs was determined on the basis of the recorded static friction force values. The test results show a significant influence of the rate of increase in the motion driving force on the values of static friction resistance. This is mainly due to the viscoelastic properties of polymers.

Natural maize phytochemicals for control of maize mycoflora and aflatoxigenic fungi

2009 ◽  
Vol 2 (3) ◽  
pp. 305-312 ◽  
Author(s):  
A. Nesci ◽  
S. Marín ◽  
M. Etcheverry ◽  
V. Sanchis
Keyword(s):  
Ferulic Acid ◽  
Incubation Period ◽  
Cinnamic Acid ◽  
Inhibitory Effect ◽  
Aspergillus Section Flavi ◽  
Aflatoxigenic Fungi ◽  
Incubation Periods ◽  
Maize Grain ◽  
Aflatoxin B ◽  
Aspergillus Section

This research was undertaken to evaluate the effects of the natural phytochemicals trans-cinnamic acid (CA) alone at concentrations of 20 and 25 mM, ferulic acid (FA) at concentration of 30 mM and two mixtures, CA-FA (20+30 mM) and CA-FA (25+30 mM) on natural maize mycoflora, Aspergillus section Flavi population and aflatoxin B1 production. These studies were carried out in maize grain in relation to a water activity of 0.99, 0.97 and 0.94. CA at 25 mM and the mixture CA-FA (25+30 mM) were the most effective treatments at inhibiting natural maize mycoflora at all aw assayed after 11 and 35 days of incubation at 25 °C. In general, 20 mM CA caused complete inhibition of Aspergillus section Flavi population at all aw values tested during all incubation period without an additional inoculum. 20 mM CA and 25 mM CA showed the major inhibitory effect on aflatoxin B1 accumulation of control and Aspergillus section Flavi additionally inoculated during all incubation periods. The data showed that CA and FA could be considered as effective fungitoxicants for natural maize mycoflora and aflatoxigenic fungi in the aw range 0.99 to 0.94. The information obtained shows promise for controlling aflatoxigenic fungi in stored maize.

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