scholarly journals MICROSTRUCTURE AND WEAR RESISTANCE OF A COMPOSITE Gr/Al2O3/Al PRODUCED BY RECIPROCATING EXTRUSION

2012 ◽  
Vol 05 ◽  
pp. 646-653
Author(s):  
Z. M. Zhang ◽  
G. P. Zhu ◽  
C. J. Xu ◽  
B. Hu
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Extrusion Process ◽  
Pure Aluminium ◽  
Low Friction ◽  
Graphite Particles ◽  
Al Composite ◽  
Alumina Particles ◽  
The Matrix ◽  
Reciprocating Extrusion

A reciprocating extrusion process was used to produce graphite and alumina reinforced pure aluminium composite. The graphite particles (0~5vol%), alumina particles (10 vol%) and pure aluminium particles (balanced) were dehydrated separately at 70°C in vacuum for 3 hours, and then mixed together. A round billet with 50 mm in diameter was prepared by hot pressing at 350°C with the mixed particles and then extruded to a fully-consolidated goblet-like sample at 480°C and 430MPa by reciprocating extrusion. The results showed that all reinforced particles were refined and uniformly distributed in the matrix by reciprocation extrusion severe plastic deformation. The presence of graphite particles caused the reduction in the friction coefficient and wear rate of the Gr / Al 2 O 3/ Al composite. Compared with the composite prepared only by alumina particles (10 vol%) and pure aluminium particles, the friction coefficient and wear rate of the Gr / Al 2 O 3/ Al composite, which contains 5vol% graphite and 10vol% alumina particles, decreased 45.3% and 33.5%, respectively, and thereafter it displays an excellent combination of low friction coefficient (0.37) and wear rate (2.2×10-7mm3/(N.m)), and appears to be more promising.

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/

scholarly journals Influence of load and reinforcement content on selected tribological properties of Al/SiC/Gr hybrid composites

2018 ◽  
Vol 18 (18) ◽  
pp. 18-23 ◽  
Author(s):  
Sandra Veličković ◽  
Slavica Miladinović ◽  
Blaža Stojanović ◽  
Ružica R. Nikolić ◽  
Branislav Hadzima ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Metal Matrix ◽  
Hybrid Composites ◽  
Tribological Characteristics ◽  
Volume Fractions ◽  
Sic Particles ◽  
The Matrix

Abstract Hybrid materials with the metal matrix are important engineering materials due to their outstanding mechanical and tribological properties. Here are presented selected tribological properties of the hybrid composites with the matrix made of aluminum alloy and reinforced by the silicon carbide and graphite particles. The tribological characteristics of such materials are superior to characteristics of the matrix – the aluminum alloy, as well as to characteristics of the classical metal-matrix composites with a single reinforcing material. Those characteristics depend on the volume fractions of the reinforcing components, sizes of the reinforcing particles, as well as on the fabrication process of the hybrid composites. The considered tribological characteristics are the friction coefficient and the wear rate as functions of the load levels and the volume fractions of the graphite and the SiC particles. The wear rate increases with increase of the load and the Gr particles content and with reduction of the SiC particles content. The friction coefficient increases with the load, as well as with the SiC particles content increase.

Prediction of Wear Rate Dispersion in Mixed Lubrication

2005 ◽  
Author(s):  
F. Robbe-Valloire ◽  
R. Progri ◽  
B. Paffoni ◽  
R. Gras
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Boundary Lubrication ◽  
Mixed Lubrication ◽  
Tribological Behaviour ◽  
Low Friction ◽  
Local Boundary ◽  
Physico Chemical ◽  
Lubricant Films ◽  
Second Category

Mixed lubrication is usually related to the partition of contacts, and these latter may be divided into two categories. The first includes all asperities working in thin lubricated film (physico-chemical film) conditions. This situation corresponds to local boundary lubrication and is characterised by a local friction coefficient around 0.1. The second category contains all other asperity types. Due to the existence of a thick lubricant films asperities belonging to the second category exhibit a low friction coefficient. The global tribological behaviour for a given contact, however, is function of both categories, since it involves asperities from both categories.

Al2O3/Al Composites Consolidated from Alumina and Aluminum Particulates by Reciprocating Extrusion

2011 ◽  
Vol 311-313 ◽  
pp. 63-67
Author(s):  
Zhong Ming Zhang ◽  
Bo Hu ◽  
Feng Tao Gao ◽  
Jin Cheng Wang
Keyword(s):  
Tensile Strength ◽  
Volume Fraction ◽  
Pure Aluminum ◽  
Testing Machine ◽  
Aluminum Matrix ◽  
Stir Casting ◽  
Extrusion Process ◽  
Hardness Tester ◽  
Alumina Particles ◽  
Reciprocating Extrusion

MMCs can be usually fabricated by powder metallurgy, stir casting and spray co-deposition, etc. Al2O3/Al composites were produced by means of reciprocating extrusion with alumina and pure aluminum particulates in the present study. The microstructure was analyzed by scanning electronic microscope, and the mechanical properties were measured by hardness tester and universal testing machine, respectively. The results showed that Al2O3/Al composites with as high as 20 vol.% alumina can be successfully produced by reciprocating extrusion. During reciprocating extrusion process, the reinforced alumina particles can be fragmentized and uniformly distributed in the aluminum matrix. The tensile strength and hardness of the composites increase as volume fraction of alumina particles increases, whereas the elongation decreases. Compared with the pure aluminum compact, the tensile strength and hardness of the composite with 20 vol.% alumina particles is 29.3% and 93.5% higher, respectively; whereas the elongation decreases 66.6%, and the fracture mechanism of the composites is attributed to ductile rupture.

Damping behavior of in situ Al–(graphite, Al4C3) composites produced by reciprocating extrusion

2001 ◽  
Vol 16 (5) ◽  
pp. 1372-1380 ◽  
Author(s):  
Hsu-Shen Chu ◽  
Kuo-Shung Liu ◽  
Jien-Wei Yeh
Keyword(s):  
Alloy Powder ◽  
Damping Capacity ◽  
High Modulus ◽  
Graphite Particles ◽  
Solution Treated ◽  
Damping Behavior ◽  
The Matrix ◽  
Graphite Composites ◽  
Reciprocating Extrusion

The effect of graphite particles on the damping behavior of 6061 Al–graphite composites was investigated with an aim to develop a high damping, stiffness, and hardness material. The composites were processed by mixing 6061 alloy powder with graphite particles, hot pressed as a billet and consolidated by reciprocating extrusion 10 times. The results showed that the graphite particles were greatly refined and niformly distributed in the matrix. The graphite in situ reacted with the Al matrix to orm fine dispersed Al4C3 particles during both reciprocating extrusion and subsequent olution treatment. The Al4C3 phase could result in a pronounced dispersion trengthening effect. The damping capacity of the composite increased with increasing raphite content. The composite showed a peak in damping capacity during aging reatment. The 6061 Al–20% (graphite, Al4C3) composite solution-treated for 24 h and eak-aged displayed an excellent combination of damping capacity, stiffness, and ardness. The composite retained high damping while maintaining a high modulus ecause of the coexistence of graphite and Al4C3. The operative damping mechanisms, ncluding intrinsic damping of graphite particle, interface damping, dislocation amping, and grain boundary damping, are discussed with consideration of material icrostructure.

scholarly journals Micro/Nanostructure and Tribological Characteristics of Pressureless Sintered Carbon Nanotubes Reinforced Aluminium Matrix Composites

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
P. Manikandan ◽  
R. Sieh ◽  
A. Elayaperumal ◽  
H. R. Le ◽  
S. Basu
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
High Energy ◽  
Wear Behaviour ◽  
Powder Metallurgy Method ◽  
Pure Aluminium ◽  
Matrix Composites ◽  
Reinforced Composites ◽  
Tribological Behaviour ◽  
Mechanically Alloyed

This study reports the manufacture, microstructure, and tribological behaviour of carbon nanotube reinforced aluminium composites against pure aluminium. The specimens were fabricated using powder metallurgy method. The nanotubes in weight percentages of 0.5, 1.0, 1.5, and 2.0 were homogeneously dispersed and mechanically alloyed using a high energy ball milling. The milled powders were cold compacted and then isothermally sintered in air. The density of all samples was measured using Archimedes method and all had a relative density between 92.22% and 97.74%. Vickers hardness increased with increasing CNT fraction up to 1.5 wt% and then reduced. The microstructures and surfaces were investigated using high resolution scanning electron microscope (SEM). The tribological tests showed that the CNT reinforced composites displayed lower wear rate and friction coefficient compared to the pure aluminium under mild wear conditions. However, for severe wear conditions, the CNT reinforced composites exhibited higher friction coefficient and wear rate compared to the pure aluminium. It was also found that the friction and wear behaviour of CNT reinforced composites is significantly dependent on the applied load and there is a critical load beyond which CNTs could have adverse impact on the wear resistance of aluminium.

Tribological Properties Between a-C:H Coatings and SiO2 at High Temperature

2020 ◽  
Author(s):  
Noritsugu Umehara ◽  
Kota Konishi ◽  
Motoyuki Murashima ◽  
Takayuki Tokoroyama
Keyword(s):  
High Temperature ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Friction And Wear ◽  
Wear Track ◽  
Severe Damage ◽  
Friction Test ◽  
Low Friction ◽  
Disk Friction

Abstract Tribological properties of a-C:H coatings has been investigated in various friction conditions. It is clear that temperature and mating materials give effects on tribological properties. In this study, we especially focus on the effect of mating material on its tribological properties of a-C:H coatings. Ball-on-disk friction test is conducted between a-C:H coating and 5 kinds of mating material, which is SiC, SiC(O)_800 (SiC oxidized at 800°C), SiC(O)_1050°C, SiC(O)_1300°C, and Quartz glass. It is found that a-C:H coatings shows low friction coefficient and low specific wear rate when O/Si ratio of the element content of mating material is 2, in other words, mating material is SiO2. In the wear scar of a-C:H coating after friction test with SiC, severe damage was confirmed. It is considered that a-C:H coating and SiO2 show low adhesion even at high temperature, which leads low friction and wear. Compared SiC(O) with Quartz, the friction coefficients with a-C:H coatings are respectively 0.013 and 0.038. Even though SiC(O) and Quartz are both SiO2, the tribological properties are different. On the wear track of SiC(O), transferred things from a-C:H coating are confirmed.

Micromechanical Behaviour of Amorphous Hydrogenated Silicon Carbide Films

1993 ◽  
Vol 308 ◽  
Author(s):  
J. Meneve ◽  
R. Jacobs ◽  
F. Lostak ◽  
L. Eersels ◽  
E. Dekempeneer ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Chemical Vapour ◽  
Diamond Like Carbon ◽  
Ambient Atmosphere ◽  
Low Friction ◽  
Hydrogenated Silicon ◽  
Amorphous Hydrogenated Silicon ◽  
Low Wear

ABSTRACTAmorphous hydrogenated silicon carbide (a-Si1-xCx:H) films (x = 0.65 to 1) were deposited by radio frequency plasma assisted chemical vapour deposition (RF-PACVD). Their friction and wear properties were investigated by means of a conventional ball-on-disk apparatus. The results were correlated with film mechanical properties. It was found that adding silicon to a-C:H (also called diamond-like carbon (DLC)) films reduces the hardness, elastic modulus and internal stress values by 15 to 30 %. Scratch testing induces film spallation from stainless steel substrates at low loads (1 N). In the low normal load (1 N) ball-on-disk tests under humid N2 conditions, a-Si1-xCx:H films (0.7 < x < 0.9) combine a very low wear rate of both the film and the counterbody with a steady state low friction coefficient below 0.1. For higher loads (5 and 10 N), however, this low friction coefficient only lasts for a relatively short time. In this case, the harder diamond-like carbon films perform tribologically better because of their higher wear resistance, low wear rate of the counterbody and generally low friction coefficients between 0.15 and 0.35 in a humid ambient atmosphere. In a dry N2 atmosphere, pure DLC films perform tribologically better than a-S1-xCx:H films in all respects.

Tribological Properties of Polymer Composites Reinforced with Silver Particles

2014 ◽  
Vol 1036 ◽  
pp. 65-70
Author(s):  
Jakub Wieczorek ◽  
Agata Blacha-Grzechnik ◽  
Jerzy Łabaj ◽  
Grzegorz Siwiec
Keyword(s):  
Friction Coefficient ◽  
Waste Materials ◽  
Matrix Composites ◽  
Silver Particles ◽  
Low Friction ◽  
The Matrix ◽  
Composite Production ◽  
Block Test ◽  
Sliding Distance ◽  
Matrix Powder

The paper presents results of investigations on a potential for utilisation of waste materials, containing silver powders, ceramics and polymer, for production of PTFE-matrix composites. The waste is a mix of Ag powders (10 – 15%), SiC and Al2O3 powders (20 – 50%) and polymeric powders (20 –50%). For composite production, high-temperature press moulding method was applied. Reinforcing materials and the matrix powder were mixed and subjected to the pressing process in a graphite mould at 350oC. Composite specimens containing 25% Ag, 50% Ag and 75% Ag were obtained. For the obtained composites, density, HB hardness and a friction coefficient were determined. The friction coefficient was evaluated in the “pin-on-block” test with the sliding distance of 2500 m and a load of 25 N with no lubrication. Wear of the composites was assessed based on a profilometry analysis. The obtained results suggest that the composites may be applied for manufacturing of components resistant to abrasive wear with a required, low friction coefficient.

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