Investigating the effect of load on tribological behaviour of Cu composite reinforced with Ti2SnC particles

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fangfang Zhang ◽  
Fengyun Yan ◽  
Tijun Chen ◽  
Xiaohong Li ◽  
Zhen Wang
Keyword(s):  
Mechanical Test ◽  
Electrical Contact ◽  
Mixing Layer ◽  
Tribological Behaviour ◽  
Mechanical Mixing ◽  
Content Type ◽  
Light Load ◽  
Powder Sintering ◽  
The Matrix ◽  
Sliding Electrical Contact

Purpose This paper aims to study the effect of load on the tribological behaviour of Cu-based composites, so as to obtain a suitable applied load on these composites. Design/methodology/approach Cu-based composites were prepared by powder sintering with direct current electric current heating and tested by Universal Mechanical Test-3 with a ball-on-disk at room temperature. Findings The results showed that Cu-based composites are might suitable for working under low load. There is only mild damage on the surface under a load of 2 N. While it has microcracks and shows signs of cavitation at a certain depth at 20 N and 50 N. In addition, it is evident that there are three zones in the cross-section of the matrix, namely, a mechanical mixing layer, ceramic layer and substrate, respectively. Originality/value There are two wear mechanisms at different loads, and the evolution of worn surfaces with sliding time is also involved. Thus, the developed material can be used for light load sliding electrical contact material applications.

A study on tribological behaviour and analysis of ZnO reinforced AA6061 matrix composites fabricated by stir casting route

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sakthi Sadhasivam RM ◽  
Ramanathan K. ◽  
Bhuvaneswari B.V. ◽  
Raja R.
Keyword(s):  
Wear Rate ◽  
Sliding Wear ◽  
Stir Casting ◽  
Industrial Applications ◽  
Wear Behaviour ◽  
Matrix Composites ◽  
Tribological Behaviour ◽  
Content Type ◽  
Zno Particles ◽  
The Matrix

Purpose The most promising replacements for the industrial applications are particle reinforced metal matrix composites because of their good and combined mechanical properties. Currently, the need of matrix materials for industrial applications is widely satisfied by aluminium alloys. The purpose of this paper is to evaluate the tribological behaviour of the zinc oxide (ZnO) particles reinforced AA6061 composites prepared by stir casting route. Design/methodology/approach In this study, AA6061 aluminium alloy matrix reinforced with varying weight percentages (3%, 4.5% and 6%) of ZnO particles, including monolithic AA6061 alloy samples, is cast by the most economical fabrication method, called stir casting. The prepared sample was subjected to X-ray photoelectron spectroscopy (XPS) analysis, experimental density measurement by Archimedian principle and theoretical density by rule of mixture and hardness test to investigate mechanical property. The dry sliding wear behaviour of the composites was investigated using pin-on-disc tribometer with various applied loads of 15 and 20 N, with constant sliding velocity and distance. The wear rate, coefficient of friction (COF) and worn surfaces of the composite specimens and their effects were also investigated in this work. Findings XPS results confirm the homogeneous distribution of ZnO microparticles in the Al matrix. The Vickers hardness result reveals that higher ZnO reinforced (6%) sample have 34.4% higher values of HV than the monolithic aluminium sample. The sliding wear tests similarly show that increasing the weight percentage of ZnO particles leads to a reduced wear rate and COF of 30.01% and 26.32% lower than unreinforced alloy for 15 N and 36.35% and 25% for 20 N applied load. From the worn surface morphological studies, it was evidently noticed that ZnO particles dispersed throughout the matrix and it had strong bonding between the reinforcement and the matrix, which significantly reduced the plastic deformation of the surfaces. Originality/value The uniqueness of this work is to use the reinforcement of ZnO particles with AA6061 matrix and preparing by stir casting route and to study and analyse the physical, hardness and tribological behaviour of the composite materials.

Interaction of tungsten in dry sliding against steel under high density electric current

2019 ◽  
pp. 101-109 ◽  
Author(s):  
M. I. Aleutdinova ◽  
V. V. Fadin ◽  
Yu. P. Mironov
Keyword(s):  
Electrical Contact ◽  
Analysis Data ◽  
Dry Sliding ◽  
Sliding Surface ◽  
X Ray ◽  
Sliding Surfaces ◽  
Quenched Steel ◽  
Sliding Electrical Contact ◽  
A Current ◽  
Tungsten Steel

The possibility of creating a wear-resistant dry sliding electrical contact tungsten/steel was studied. It was shown that tungsten caused severe wear of the quenched steel counterbody due to unlimited plastic flow of its surface layer at a current density up to 150 A/cm2 . This indicated the impossibility of achieving satisfactory characteristics of such a contact. Low electrical conductivity and wear resistance of the contact tungsten/steel were presented in comparison with the known high copper/steel contact characteristics under the same conditions. X-ray phase analysis data of the steel sliding surfaces made it possible to state that the cause of the unsatisfactory sliding of tungsten was the absence of the necessary concentration of FeO oxide on the sliding surface of the steel. 

Study on high-temperature wear and mechanism of Al-Si/graphite composites prepared by the die-casting process

2020 ◽  
Vol 72 (10) ◽  
pp. 1153-1158 ◽  
Author(s):  
Yafei Deng ◽  
Xiaotao Pan ◽  
Guoxun Zeng ◽  
Jie Liu ◽  
Sinong Xiao ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Peer Review ◽  
Die Casting ◽  
Casting Machine ◽  
Injection Pressure ◽  
Casting Process ◽  
Matrix Alloy ◽  
Content Type ◽  
The Matrix

Purpose This paper aims to improve the tribological properties of aluminum alloys and reduce their wear rate. Design/methodology/approach Carbon is placed in the model at room temperature, pour 680°C of molten aluminum into the pressure chamber, and then pressed it into the mold containing carbon felt through a die casting machine, and waited for it to cool, which used an injection pressure of 52.8 MPa and held the same pressure for 15 s. Findings The result indicated that the mechanical properties of matrix and composite are similar, and the compressive strength of the composite is only 95% of the matrix alloy. However, the composite showed a low friction coefficient, the friction coefficient of Gr/Al composite is only 0.15, which just is two-third than that of the matrix alloy. Similarly, the wear rate of the composite is less than 4% of the matrix. In addition, the composite can avoid severe wear before 200°C, but the matrix alloy only 100°C. Originality/value This material has excellent friction properties and is able to maintain this excellent performance at high temperatures. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0454/

Fatigue behavior of precipitation strengthened Cu–Ni–Si alloy modified by Cr and Zr addition

2020 ◽  
Vol 11 (6) ◽  
pp. 861-873
Author(s):  
Ş. Hakan Atapek ◽  
Spiros Pantelakis ◽  
Şeyda Polat ◽  
Apostolos Chamos ◽  
Gülşah Aktaş Çelik
Keyword(s):  
Design Methodology ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Lower Stress ◽  
Content Type ◽  
Hardened Alloy ◽  
Zr Addition ◽  
Nucleation Sites ◽  
The Matrix ◽  
Lower Stress Level

Purpose The purpose of this paper is to investigate the fatigue behavior of precipitation-strengthened Cu‒2.55Ni‒0.55Si alloy, modified by the addition of 0.25 Cr and 0.25 Zr (wt%), using mechanical and fractographical studies to reveal the effect of microstructural features on the fracture. Design/methodology/approach For strengthening, cast and hot forged alloy was subjected to solution annealing at 900°C for 60 min, followed by quenching in water and then aging at 490°C for 180 min. Precipitation-hardened alloy was exposed to fatigue tests at R=−1 and different stress levels. All fracture surfaces were examined within the frame of fractographical analysis. Findings Fine Ni-rich silicides responsible for the precipitation strengthening were observed within the matrix and their interactions with the dislocations at lower stress level resulted in localized shearing and fine striations. Although, by the addition of Cr and Zr, the matrix consisted of hard Ni, Zr-rich and Cr-rich silicides, these precipitates adversely affected the fatigue behavior acting as nucleation sites for cracks. Originality/value These findings contribute to the present knowledge by revealing the effect of microstructural features on the mechanical behavior of precipitation-hardened Cu‒Ni‒Si alloy modified by Cr and Zr addition.

Design of the variable frequency oscillator in DC-DC converter

Circuit World ◽  
2019 ◽  
Vol 45 (2) ◽  
pp. 80-85
Author(s):  
Tian Lei ◽  
Nan Gong ◽  
Li Wang ◽  
Qin Qin Li ◽  
Heng Wei Wang
Keyword(s):  
Supply Voltage ◽  
Operating Frequency ◽  
Maximum Deviation ◽  
Variable Frequency ◽  
Cmos Process ◽  
Power Supply Voltage ◽  
Output Stage ◽  
Content Type ◽  
Oscillator Frequency ◽  
Light Load

Purpose Because of the logic delay in the converter, the minimum turn on time of the switch is influenced by the constant time. When the inductor current gets to the threshold of the chip, the control signal will delay for a period. This makes the inductor current rising with the increasing of the clock and leads to the load current out of control. Thus, this paper aims to design an oscillator with a variable frequency protection function. Design/methodology/approach This paper presents an oscillator with the reducing frequency applied in the DC-DC converter. When the converter works normally, the operating frequency of the oscillator is 1.5 MHz. So the inductor current has enough time to decay and prevent the power transistor damaging. After the abnormal condition, the converter returns to the normal operating mode automatically. Findings Based on 0.5 µm CMOS process, simulated by the HSPICE, the simulation results shows that the frequency of the oscillator linearly decreases from 1.5 MHz to 380 KHz when the feedback voltage less than 0.2 V. The maximum deviation of the oscillator frequency is only 6 per cent from −50°C to 125°C within the power supply voltage of 2.7-5.5 V. Originality/value When the light load occurs at the output stage, the oscillator frequency will decrease as the load voltage drops. The test results shows that when the circuit works in the normal condition, the oscillator frequency is 1.5 MHz. When the load decreased, the operating frequency is dropped dramatically.

The Mechanism of Getting New Composite Polymer Materials with Improved Hardness Properties

2021 ◽  
Vol 887 ◽  
pp. 85-90
Author(s):  
L.S. Elbakyan ◽  
I.V. Zaporotskova ◽  
D.E. Vilkeeva
Keyword(s):  
Carbon Nanotubes ◽  
Polymer Material ◽  
Single Layer ◽  
Scientific Basis ◽  
Strength Properties ◽  
Polymer Materials ◽  
Mechanical Mixing ◽  
Material Component ◽  
Adsorption Interaction ◽  
The Matrix

The main aims and the objectives of the study focused on solving current problems of nanomaterial science of new materials – creating the scientific basis for competitive methods of obtaining and controlling new composite materials having improved strength properties based on carbon-containing polymer matrices with nanotubes stabilized in them. A technology for obtaining experimental samples of nanocompositional polymer material based on polymethylmethacrylate, polybutylmethacrylate, and methacrylic acid doped with carbon nanotubes has been developed, using ultrasonic action and mechanical mixing of the composite mixture to achieve the most uniform distribution of nanotubes in the matrix. To determine the possibility of implementing the mechanism of adsorption interaction of the studied polymer material with the surface of carbon nanotubes, DFT calculations of the interaction of the polymer material component and single-layer carbon nanotubes of various types have been done.

Tribological performance of self-lubricated polyamide6/boric oxide composites after water conditioning

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kawaljit Singh Randhawa ◽  
Ashwin Patel
Keyword(s):  
Friction Coefficient ◽  
Abrasion Resistance ◽  
Tribological Performance ◽  
Boric Oxide ◽  
Resistance Testing ◽  
Tribological Behaviour ◽  
Content Type ◽  
Wear Rates ◽  
Water Conditioning ◽  
Oxide Composites

Purpose This paper aims to investigate the tribological performance, i.e. abrasion resistance, friction coefficient and wear rates, of self-lubricated water conditioned polyamide6/boric oxide composites. Design/methodology/approach Polyamide6 and polyamide6/boric oxide self-lubricated composites were immersed in water for 15 days to analyze the effect of water conditioning on friction, wear and abrasion resistance. Tribological testing on pin-on-disc tribometer and abrasion resistance testing on TABER abrader were performed to see the friction coefficient and wear rates of materials. The scanning electron microscopy (SEM) characterizations were performed to analyze the wear tracks. Findings Tribological testing results revealed the loss in abrasive resistance, but there was an improvement in frictional coefficient and wear rates with steel after water absorption. The SEM images clearly show less depth of wear tracks in water-conditioned materials than dry ones. Water conditioning was found supportive in the formation of smooth lubricating transfer film on steel disc during the tribological testing. Originality/value The tribological behaviour of polymer composites is different in dry and in high humidity or water conditions. Experiments were performed to investigate B2O3 solid lubricant filler effectiveness on tribological behaviour of water-conditioned polyamide composites. Bonding between polyamide6 and water molecules plus the formation of orthoboric acid was found advantageous in decreasing the friction coefficient and wear rates of composites.

Enhancing the tensile strength of SiC reinforced aluminium- based functionally graded structure through the mixture design approach

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
M. Poornesh ◽  
Shreeranga Bhat ◽  
E.V. Gijo ◽  
Pavana Kumara Bellairu
Keyword(s):  
Tensile Strength ◽  
Composite Structure ◽  
Centrifugal Casting ◽  
Matrix Material ◽  
Stir Casting ◽  
Mixture Design ◽  
Functionally Graded ◽  
Content Type ◽  
Functionally Graded Composite ◽  
The Matrix

PurposeThis article aims to study the tensile properties of a functionally graded composite structure with Al–18wt%Si alloy as the matrix material and silicon carbide (SiC) particles as the reinforcing element. More specifically, the study's primary objective is to optimize the composition of the material elements using a robust statistical approach.Design/methodology/approachIn this research, the composite material is fabricated using a combination of stir casting and the centrifugal casting technique. Moreover, the test specimen required to study the tensile strength are prepared according to the ASTM (American Society for Testing and Materials) standards. Eventually, optimal composition to maximize the tensile property of the material is determined using the mixture design approach.FindingsThe investigation results imply that the addition of the SiC plays a crucial role in increasing the tensile strength of the composite. The optical microstructural images of the composite show the adequate distribution of the reinforcing particles with the matrix. The proposed regression model shows better predictability of tensile strength. In addition, the methodology aids in optimizing the mixture component values to maximize the tensile strength of the produced functionally graded composite structure.Originality/valueLittle work has been reported so far where a hypereutectic Al–Si alloy is considered the matrix material to produce the composite structure. The article attempts to make a composite structure by using a combination of stir casting and centrifugal casting. Furthermore, it employs the mixture design to optimize the composition and predict the model of the study, which is one of a kind in the field of material science.

Tribological and electrical behavior of Cu-based composites with addition of Ti-doped NbSe2 nanoplatelets

2018 ◽  
Vol 70 (3) ◽  
pp. 560-567 ◽  
Author(s):  
Jian Feng Li ◽  
Qin Shi ◽  
HeJun Zhu ◽  
ChenYu Huang ◽  
Shuai Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Friction Coefficient ◽  
Electrical Properties ◽  
Tribological Properties ◽  
Solid State Reaction ◽  
Electrical Contact ◽  
Solid State Reaction Method ◽  
Content Type ◽  
Reaction Method

Purpose This paper aims to clarify the size and morphology of transition metal dichalcogenides has an impact on lubrication performance of Cu-based composites. This study is intended to show that Cu-based electrical contact materials containing Nb0.91Ti0.09Se2 have better electrical and tribological properties than those containing NbSe2. The tribological properties of Cu-based with different Ti-dopped NbSe2 content were also discussed. Design/methodology/approach The NbSe2 and Nb0.91Ti0.09Se2 particles were fabricated by thermal solid state reaction method. The powder metallurgy technique was used to fabricate composites with varying Nb0.91Ti0.09Se2 mass fraction. The phase composition of Cu-based composites was identified by X-ray diffraction, and the morphology of NbSe2/Nb0.91Ti0.09Se2 and the worn surface of composites were characterized by scanning electron microscopy and transmission electron microscopy. In addition, the tribological properties of composites were appraised using a ball-on-disk multi-functional tribometer. The data of friction coefficient and resistivity were analyzed and the corresponding conclusion was drawn. Findings In comparison with the pure copper, Cu-based composites containing Nb0.91Ti0.09Se2/NbSe2 had a lower friction coefficient, illustrating the Nb0.91Ti0.09Se2 with nano-size particles prepared in this work is a perfect choice for the fabrication of excellent electrical contact composites. Compared to composites with NbSe2, composites containing Nb0.91Ti0.09Se2 have better tribological and electrical properties. Research limitations/implications Because of the use of thermal solid state reaction method, the size of NbSe2 and Nb0.91Ti0.09Se2 is relatively large. Therefore, the fabrication of finer particles of Nb0.91Ti0.09Se2 is encouraged. Originality/value In this paper, the authors discuss the tribological and electrical properties of Cu-based composites, and the value of optimum obtained as Nb0.91Ti0.09Se2 content is 15 Wt.%.

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