scholarly journals Surface Modification of Ti-6Al-4V Alloy by Electrical Discharge Coating Process Using Partially Sintered Ti-Nb Electrode

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1006 ◽  
Author(s):  
Chander Prakash ◽  
Sunpreet Singh ◽  
Catalin Pruncu ◽  
Vinod Mishra ◽  
Grzegorz Królczyk ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Electric Discharge ◽  
Composite Layer ◽  
Surface Hardness ◽  
Thick Layer ◽  
Dielectric Fluid ◽  
Machining Processes ◽  
Coated Surface ◽  
Coated Layer

In the present research, a composite layer of TiO2-TiC-NbO-NbC was coated on the Ti-64 alloy using two different methods (i.e., the electric discharge coating (EDC) and electric discharge machining processes) while the Nb powder were mixed in dielectric fluid. The effect produced on the machined surfaces by both processes was reported. The influence of Nb-concentration along with the EDC key parameters (Ip and Ton) on the coated surface integrity such as surface topography, micro-cracks, coating layer thickness, coating deposition, micro-hardness has been evaluated as well. It has been noticed that in the EDC process the high peak current and high Nb-powder concentration allow improvement in the material migration, and a crack-free thick layer (215 μm) on the workpiece surface is deposited. The presence of various oxides and carbides on the coated surface further enhanced the mechanical properties, especially, the wear resistance, corrosion resistance and bioactivity. The surface hardness of the coated layer is increased from 365 HV to 1465 HV. Furthermore, the coated layer reveals a higher adhesion strength (~118 N), which permits to enhance the wear resistance of the Ti-64 alloy. This proposed technology allows modification of the mechanical properties and surface characteristics according to an orthopedic implant’s requirements.

scholarly journals Simulation of Neutron/Self-Emitted Gamma Attenuation and Effects of Silane Surface Treatment on Mechanical and Wear Resistance Properties of Sm2O3/UHMWPE Composites

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3390
Author(s):  
Donruedee Toyen ◽  
Yupadee Paopun ◽  
Dararat Changjan ◽  
Ekachai Wimolmala ◽  
Sithipong Mahathanabodee ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Surface Treatment ◽  
Gamma Rays ◽  
Surface Hardness ◽  
Thermal Neutrons ◽  
Simulation Code ◽  
Neutron Shielding ◽  
Wear Rates ◽  
Uhmwpe Composites

This work reports on the simulated neutron and self-emitted gamma attenuation of ultra-high-molecular-weight polyethylene (UHMWPE) composites containing varying Sm2O3 contents in the range 0–50 wt.%, using a simulation code, namely MCNP-PHITS. The neutron energy investigated was 0.025 eV (thermal neutrons), and the gamma energies were 0.334, 0.712, and 0.737 MeV. The results indicated that the abilities to attenuate thermal neutrons and gamma rays were noticeably enhanced with the addition of Sm2O3, as seen by the increases in µm and µ, and the decrease in HVL. By comparing the simulated neutron-shielding results from this work with those from a commercial 5%-borated PE, the recommended Sm2O3 content that attenuated thermal neutrons with equal efficiency to the commercial product was 11–13 wt.%. Furthermore, to practically improve surface compatibility between Sm2O3 and the UHMWPE matrix and, subsequently, the overall wear/mechanical properties of the composites, a silane coupling agent (KBE903) was used to treat the surfaces of Sm2O3 particles prior to the preparation of the Sm2O3/UHMWPE composites. The experimental results showed that the treatment of Sm2O3 particles with 5–10 pph KBE903 led to greater enhancements in the wear resistance and mechanical properties of the 25 wt.% Sm2O3/UHMWPE composites, evidenced by lower specific wear rates and lower coefficients of friction, as well as higher tensile strength, elongation at break, and surface hardness, compared to those without surface treatment and those treated with 20 pph KBE903. In conclusion, the overall results suggested that the addition of Sm2O3 in the UHMWPE composites enhanced abilities to attenuate not only thermal neutrons but also gamma rays emitted after the neutron absorption by Sm, while the silane surface treatment of Sm2O3, using KBE903, considerably improved the processability, wear resistance, and strength of the composites.

scholarly journals EFFECT OF ADDING BORON CARBIDE (B4C) TO POLYMER FOR PRODUCING SURFACE COMPOSITE BY FRICTION STIR PROCESSING

2018 ◽  
Vol 18 (3) ◽  
pp. 436-445
Author(s):  
Bashaer A Habeeb ◽  
Ahmed O Al-Roubaiy
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Friction Stir Processing ◽  
Composite Layer ◽  
Wear Test ◽  
Homogeneous Distribution ◽  
Cylindrical Shape ◽  
Test Results ◽  
Processing Technologies ◽  
Friction Stir

Friction stir processing (FSP) is a new solid state technique, it is employed for theimprovement of the mechanical properties of a material and the production of surface layercomposites instead of conventional processing technologies. This research aims to study theability of applying Friction Stir Processing (FSP) to modify the surface of high densitypolyethylene (HDPE) reinforcing by B4C with a particle size of 0.4?m, Groove in themiddle of HDPE surface made to fill by B4C. Varity in the groove depth (0.6, 1.2 and1.8)mm used according to B4C ratio on HDPE substrate particles. Friction stir process wascarried out, using tool with cylindrical shape of pin and shoe tool to produce surface layercomposite. The effect of processing parameters including rotational and transverse speeds onthe mechanical properties of composite layer was studied. Wear test results show apronounced improvement in wear resistance of HDPE surface through reinforcementadditions of B4C at a ratio (5%, 10% and 15% ), where wear rate improved by (60%, 71%and 63%) respectively, as compared with as received HDPE, the surface compositeHDPE/B4C have good wear resistance. Hardness test results indicate that the hardness ofcomposite layer reinforced with (5%,10% and 15%) particles improved by( 26%, 35% and28% )respectively as compared with received HDPE. OM revealed that high tool rotationalspeed resulted in homogeneous distribution of B4C particles and vice versa.

scholarly journals Effects of the Prefabricated Cu-Ti Film on the Microstructure and Mechanical Properties of the Multiphase Coating by Thermo Plasma Nitriding on C17200 Cu Alloy

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 694
Author(s):  
Yandan Zhu ◽  
Mufu Yan ◽  
Quanli Zhang ◽  
Qiwen Wang ◽  
Hangyu Zhuo
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Plasma Nitriding ◽  
Surface Hardness ◽  
Cross Sectional ◽  
Cu Alloy ◽  
Cu Substrates ◽  
Modified Surface ◽  
N Compounds ◽  
Ti Films

To improve the surface wear resistance, plasma nitriding of the prefabricated Cu-Ti films on the C17200 Cu alloy is performed to investigate the effects of the composition of the Cu-Ti films on the microstructure and the mechanical properties of the modified surface. The results firstly showed that obvious microstructure evolution appeared during the thermo-plasma nitriding process, where both the surface morphology of the composed phases and the cross-sectional profiles of the multiphase coatings varied for the three types of films. Small amounts of Ti-N compounds, Be3Ti2Cu, and different types of Cu-Ti intermetallics formed in the multiphase coating after plasma nitriding, which is dependent on the composition of the prefabricated Cu-Ti film. Correspondingly, the surface hardness and the wear resistance of the C17200 Cu substrates were obviously improved, with the obtained adhesive strength of the substrate reaching a satisfactory range.

Effect of tool pin profile on the microstructure and mechanical properties of friction stir processed Al6061/Al2O3—TiB2 surface hybrid composite layer

2017 ◽  
Vol 233 (5) ◽  
pp. 900-912 ◽  
Author(s):  
Vahid M Khojastehnezhad ◽  
Hamed H Pourasl ◽  
Reza Vatankhah Barenji
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Hybrid Composites ◽  
Composite Layer ◽  
Uniform Structure ◽  
Tool Geometry ◽  
Friction Stir ◽  
Tool Pin Profile ◽  
Microstructure And Mechanical Properties ◽  
Tool Pin

The Al6061/Al2O3–TiB2 surface hybrid composites were produced using friction stir processing. The effect of the tool pin profile was investigated on the microstructure and mechanical properties including hardness and wear resistance. For this purpose, simple cylindrical, threaded cylindrical, taper, square, and triangular pin profiles were used. X-ray diffraction analysis and transmission electron microscopy were used to characterize the used powder. Light and scanning electron microscopes were utilized for the microstructural observations of the processed samples. The results showed that the distribution of Al2O3–TiB2 particles in the specimens produced using square and triangular tool pin profiles was more uniform due to their tool geometry, which results in better stirring of the material and good material flow. Consequently, a greater reduction of particle clustering was observed, and hence the mechanical properties were enhanced. Moreover, the samples produced using square and triangular pin profiles exhibited more grain refinement than the other samples. More uniform structure, less clustering, and finer grains produced by square and triangular pin profiles caused higher hardness and wear resistance of the samples.

scholarly journals Effect of pack carburizing with chicken egg shell powder agent and vibrator quenching on the mechanical properties of AISI 9310 steel

2021 ◽  
Vol 6 (12 (114)) ◽  
Author(s):  
Sinarep Sinarep ◽  
Sujita Darmo
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Cooling Rate ◽  
Surface Hardness ◽  
Specimen Surface ◽  
Hardness Number ◽  
Cooling Medium ◽  
Chicken Egg ◽  
Egg Shell ◽  
Shell Powder

The effects of vibrator quenching (QV) on the carbon content, microstructure, and mechanical properties (surface hardness number, wear resistance) in the pack carburizing of AISI 9310 steel were studied. The aim of this research is to increase the surface hardness and improve the wear resistance of AISI 9310 steel. The problem that often occurs in the quenching treatment after pack carburizing is that the thick cooling medium does not evenly wet the surface of the specimen, so that the cooling rate is not uniform, the impact is the distribution of the specimen surface hardness is not the same. Therefore, it is necessary to research the implementation of the vibrator in the quenching treatment.  The specimens were treated with pack carburizing at a temperature of 875 °C, soaking time for 3 hours. The carburizing agent consisted of chicken egg shell powder (CESP) and rice husk charcoal (RHC) with various weight ratios of 5 %:95 %, 15 %:85 %, and 30 %:70 %. Followed by quenching treatment using a 10 % cane molasses cooling medium and vibrator. Hardness testing was carried out using a Vickers microhardness tester, wear resistance test using the pin-on-disc method, and a scanning electron microscope (SEM-EDX) was used to observe changes in the microstructure and carbon elemental content on the specimen surface. The results showed that the application of VQ caused the formation of a small martensite microstructure while without VQ it was large martensite and a few of residual ferrite. The highest surface hardness number is 685 kg/mm2, the wear resistance is 0.32 cm/mg for pack carburizing, using carburizing agent 70 % RHC, 30 % CESP and VQ. VQ causes a more even distribution of the thick cane molasses cooling medium so that the cooling rate of the specimens is uniform.

scholarly journals Mechanical Properties of Multi-Walled Carbon Nanotube/Waterborne Polyurethane Conductive Coatings Prepared by Electrostatic Spraying

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 714 ◽  
Author(s):  
Fangfang Wang ◽  
Lajun Feng ◽  
Man Lu
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Wear Resistance ◽  
Carbon Nanotube ◽  
Surface Hardness ◽  
Waterborne Polyurethane ◽  
Conductive Coatings ◽  
Mwcnt Content ◽  
Electrostatic Spraying ◽  
Multi Walled Carbon Nanotube

Electrostatic spraying (ES) was used to prepare multi-walled carbon nanotube (MWCNT)/waterborne polyurethane (WPU) abrasion-proof, conductive coatings to improve the electrical conductivity and mechanical properties of WPU coatings. The dispersity of MWCNTs and the electrical conductivity, surface hardness, and wear resistance of the coating prepared by ES (ESC) were investigated. The ESC was further compared with coatings prepared by brushing (BrC). The results provide a theoretical basis for the preparation and application of conductive WPU coatings with excellent wear resistance. The dispersity of MWCNTs and the surface hardness and wear resistance of ESC were obviously better than those of BrC. With an increase in the MWCNT content, the surface hardness of both ESC and BrC went up. As the MWCNT content increased, the wear resistance of ESC first increased and then decreased, while the wear resistance of BrC decreased. It was evident that ESC with 0.3 wt% MWCNT was fully capable of conducting electricity, but BrC with 0.3 wt% MWCNT failed to conduct electricity. The best wear resistance was achieved for ESC with 0.3 wt% MWCNT. Its wear rate (1.18 × 10−10 cm3/mm N) and friction coefficient (0.28) were the lowest, which were 50.21% and 20.00% lower, respectively, than those of pure WPU ESC.

Producing a Composite Surface Using Friction Stir Processing

2007 ◽  
Author(s):  
Jun Qu ◽  
Zhili Feng ◽  
Hanbing Xu ◽  
D. Alan Frederick ◽  
Brian C. Jolly ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Friction Stir Processing ◽  
Surface Engineering ◽  
Pure Aluminum ◽  
Composite Layer ◽  
Surface Hardness ◽  
Particle Dispersion ◽  
Aluminum Surface ◽  
Composite Surface ◽  
Friction Stir

Aluminum alloys would have much wider usage in bearing applications if their wear-resistance could be significantly improved. This investigation developed a solid-state surface engineering process to form an aluminum-alumina composite surface by friction stirring ceramic particles into an aluminum surface to improve the surface hardness and wear-resistance without sacrificing the bulk ductility and conductivity. Composite layers have been successfully processed on pure aluminum (Al 1100) surfaces that have a relatively uniform particle distribution with a concentration up to 25 vol% of alumina. Microscopic examination showed that particles were severely fractured during friction stir processing and, accordingly, the particle size decreased from the original 10–50 μm to 1–5 μm in the friction stir processed composite layer. The microindentation hardness of the aluminum surface was increased from 0.33 to 0.70 GPa (HV) and the wear-resistance was improved by 30X when rubbing against a bearing steel. It has been demonstrated that powder placement methods and process parameters can be tailored to improve particle dispersion and surface hardness. Unlike most other surface engineering techniques, this process can form very thick layers, up to centimeters in thickness, avoiding delamination because of the inherent material continuity.

scholarly journals Microstructures and Mechanical Properties of Deposited Fe-8Cr-3V-2Mo-2W on SCM420 Substrate Using Directed Energy Deposition and Effect of Post- Heat Treatment

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1231
Author(s):  
Ye Eun Jeong ◽  
Jun Yeop Lee ◽  
Eun Kyung Lee ◽  
Do Sik Shim
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Wear Resistance ◽  
Energy Deposition ◽  
Surface Hardness ◽  
Steel Powder ◽  
Post Heat Treatment ◽  
Directed Energy

In this study, the Fe-8Cr-3V-2Mo-2W tool steel powder was deposited on the SCM420 substrate through the directed energy deposition (DED) process. This study focuses on the mechanical properties of the deposited Fe-8Cr-3V-2Mo-2W and the effect of heat treatment on it. The changes in the microstructural characteristics of the deposited region due to heat treatment after deposition were observed. The influence of heat treatment on the mechanical properties was then analyzed accordingly and hence, the hardness, wear, impact and tensile tests were conducted on the deposited material. These properties were compared with those of the commercial tool steel powder M2-deposited material and the carburized specimen. In the deposited Fe-8Cr-3V-2Mo-2W layer, an increased martensite phase fraction was obtained through post-heat treatment and the amount of precipitated carbides was also increased. This increased the hardness from 48 to 62 HRc after heat treatment and the wear resistance was significantly improved as well. The amount of impact energy absorbed decreased from 11 J before heat treatment to 6 J after heat treatment, but the tensile strength significantly increased from 607 to 922 MPa. When compared with the M2-deposited surface, the Fe-8Cr-3V-2Mo-2W deposits had 3% lower surface hardness and 76% lower fracture toughness but exhibited 56% higher tensile strength. When compared with the carburized SCM420, the Fe-8Cr-3V-2Mo-2W deposits exhibited 3% higher surface hardness and wear resistance, 90% lower fracture toughness and 5% higher tensile strength. This study shows that surface hardening through DED can exhibit similar or superior mechanical properties when compared to carburizing.

Effect of silver nitrate on some mechanical properties of heat polymerizing acrylic resins

2019 ◽  
Vol 14 (1) ◽  
pp. 110
Author(s):  
Assiss. Prof. Dr. Sabiha Mahdi Mahdi ◽  
Dr. Firas Abd K. Abd K.
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Silver Nitrate ◽  
Surface Hardness ◽  
Mechanical Tests ◽  
Hardness Tester ◽  
Acrylic Resins ◽  
The Difference

Aim: The aimed study was to evaluate the influence of silver nitrate on surfacehardness and tensile strength of acrylic resins.Materials and methods: A total of 60 specimens were made from heat polymerizingresins. Two mechanical tests were utilized (surface hardness and tensile strength)and 4 experimental groups according to the concentration of silver nitrate used.The specimens without the use of silver nitrate were considered as control. Fortensile strength, all specimens were subjected to force till fracture. For surfacehardness, the specimens were tested via a durometer hardness tester. Allspecimens data were analyzed via ANOVA and Tukey tests.Results: The addition of silver nitrate to acrylic resins reduced significantly thetensile strength. Statistically, highly significant differences were found among allgroups (P≤0.001). Also, the difference between control and experimental groupswas highly significant (P≤0.001). For surface hardness, the silver nitrate improvedthe surface hardness of acrylics. Highly significant differences were statisticallyobserved between control and 900 ppm group (P≤0.001); and among all groups(P≤0.001)with exception that no significant differences between control and150ppm; and between 150ppm and 900ppm groups(P>0.05).Conclusion: The addition of silver nitrate to acrylics reduced significantly the tensilestrength and improved slightly the surface hardness.

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