scholarly journals Tribological Analysis ofMg2SiParticulates Reinforced Powder Metallurgy Magnesium Alloy Composites under Oil Lubrication Condition

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Katsuyoshi Kondoh ◽  
Junko Umeda ◽  
Kenshi Kawabata
Keyword(s):  
Powder Metallurgy ◽  
Friction Coefficient ◽  
Wear Behavior ◽  
Hot Extrusion ◽  
Mg Alloys ◽  
Oil Lubrication ◽  
The Matrix ◽  
High Microhardness ◽  
Tribological Analysis ◽  
Repetition Number

For the evaluation of wear behavior of Mg composites under oil lubrication conditions, powder metallurgyMg97Y2Zn1alloy reinforced with additiveMg2Siparticles were fabricated by the repeated plastic working (RPW) and hot extrusion. The RPW process was effective in refining bothMg2Sireinforcements andα-Mg grains causing the matrix hardening. When increasing the repetition number of RPW process from 200 to 600 cycles, the particle size ofMg2Siadditives changed from 8 μm to 1~2 μm, andα-Mg grain size was 1 μm or less. With regard to the defensive and offensive properties of Mg alloys reinforced withMg2Sidispersoids, the composite had superior adhesive wear resistance compared with the conventional Mg alloys because of its extremely high microhardness of 95~180 Hv by RPW process. The uniform distribution of refinedMg2Siparticles was useful for improving both defensive and offensive properties against AZ31B counter disk specimens. TheMg2Siprominent dispersoids in the matrix were also effective in forming the oil grooves around them, and caused the low and stable friction coefficient. On the other hand, in the case of the composite containing coarseMg2Siparticles, severely deep scratches were given on the counter face of the AZ31B disk, and resulted in an unstable and high friction coefficient.

scholarly journals Grain Refinement of Ti-15Mo-3Al-2.7Nb-0.2Si Alloy with the Rotation of TiB Whiskers by Powder Metallurgy and Canned Hot Extrusion

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 126 ◽  
Author(s):  
Jiabin Hou ◽  
Lin Gao ◽  
Guorong Cui ◽  
Wenzhen Chen ◽  
Wencong Zhang ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Tensile Test ◽  
Grain Refinement ◽  
Hot Extrusion ◽  
Dislocation Motion ◽  
Continuous Dynamic Recrystallization ◽  
Grain Sizes ◽  
The Matrix ◽  
Continuous Dynamic

In situ synthesized TiB whiskers (TiBw) reinforced Ti-15Mo-3Al-2.7Nb-0.2Si alloys were successfully manufactured by pre-sintering and canned hot extrusion via adding TiB2 powders. During pre-sintering, most TiB2 were reacted with Ti atoms to produce TiB. During extrusion, the continuous dynamic recrystallization (CDRX) of β grains was promoted with the rotation of TiBw, and CDRXed grains were strongly inhibited by TiBw with hindering dislocation motion. Eventually, the grain sizes of composites decreased obviously. Furthermore, the stress transmitted from the matrix to TiBw for strengthening in a tensile test, besides grain refinement. Meanwhile, the fractured TiBw and microcracks around them contributed to fracturing.

Study on Friction Properties of Cu-Fe-Based Powder Metallurgy Materials under Dry and Wet Friction Conditions

2010 ◽  
Vol 150-151 ◽  
pp. 1806-1809 ◽  
Author(s):  
Rong Fu ◽  
Fei Gao ◽  
Bao Yun Song
Keyword(s):  
Powder Metallurgy ◽  
Friction Coefficient ◽  
High Speed ◽  
Wear Behavior ◽  
Water Film ◽  
Powder Metallurgy Process ◽  
Wet Friction ◽  
Friction Pressure ◽  
Pressure Changes ◽  
Metallurgy Process

Copper-iron-based friction materials were prepared by powder metallurgy process. The effects of friction velocity and friction pressure on friction and wear behavior of the material under dry and wet friction conditions were investigated with a constant-speed friction machine. The results show that, at low speed friction, the dry friction coefficient is higher than wet friction coefficient and the friction coefficient increases with increasing friction pressure. The reason is that the water film plays an important role in cleaning and lubricating. At high speed friction, there is not much difference between dry and wet friction coefficients and the friction coefficient is not sensitive to friction pressure changes. This is due to the metal matrix high-temperature softening, caused by high speed friction, which controls the friction properties.

scholarly journals Study on Friction and Wear Behavior of Inconel 625 Superalloy during Hot Extrusion

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Yanjiang Wang ◽  
Sixiang Zhao ◽  
Zhi Jia ◽  
Jinjin Ji ◽  
Dexue Liu ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Wear Mechanisms ◽  
Elevated Temperatures ◽  
Wear Behavior ◽  
Hot Extrusion ◽  
Specific Wear Rate ◽  
Inconel 625 ◽  
Fatigue Wear ◽  
Inconel 625 Superalloy

Friction during the hot extrusion of Inconel 625 superalloy tubes causes severe wear of the mold and plays a decisive role in the quality of the workpieces. In this paper, a ball-to-disk method was utilized to investigate the tribological behavior of Inconel 625 using two different tribological pairs, i.e., GCr15 and Si3N4, at room and elevated temperatures. Friction coefficient, specific wear rate, and morphology of worn surfaces were systematically characterized. It was found that the friction coefficients for both tribological pairs generally increased as the testing temperature increased, while the specific wear rate increased firstly and then decreased with the rise of temperature. Along with the increasing sliding speed, the friction coefficient between Inconel 625 and Si3N4 decreased monotonically, while the specific wear rate increased firstly and then decreased. Under any given testing condition, the friction coefficient and specific wear rate of the Inconel 625 for Inconel/Si3N4 pair are less than those of the Inconel/GCr15 pair. The main wear mechanisms between GCr15 and Inconel 625 are adhesive and fatigue wear at all testing temperatures. The wear mechanisms between Si3N4 and Inconel 625 are adhesive and abrasive wear at room temperature but fatigue wear at 500°C. Our findings indicate that the use of ceramic molds in the hot extrusion of Inconel 625 may significantly improve the surface qualities of the product and reduce the wear of the mold.

An Overview of Quasicrystal Reinforced Magnesium Metal Matrix Composites

2019 ◽  
Vol 969 ◽  
pp. 218-224
Author(s):  
K. Jithesh ◽  
T. Ram Prabhu ◽  
R.V. Anant ◽  
M. Arivarasu ◽  
A. Srinivasan ◽  
...  
Keyword(s):  
Interface Reaction ◽  
Secondary Reinforcement ◽  
Hot Extrusion ◽  
Casting Process ◽  
Mg Alloys ◽  
Ex Situ ◽  
Crystallographic Structure ◽  
Reaction Products ◽  
The Matrix ◽  
Strength And Stiffness

The strength of metals and their alloys are enhanced by adding secondary reinforcement particles like Conventional crystalline and non-crystalline particles such as SiC, glass and Al2O3. These particles provide weak interfacial bonding due to the crystallographic structure mismatch or undesirable interface reaction products. Quasicrystals provide strong interfaces with the matrix due to their low interfacial energy. Their low strength and stiffness make them useful in non-critical stress applications such as instrument panels, seat frames and gear box housings. Reinforcing quasicrystals to Mg alloys greatly enhances their strength or stiffness. The literature on quasicrystal (in-situ and ex-situ) reinforced Mg alloy composites are critically reviewed to show the importance of quasicrystal reinforcement in Mg alloys and the effect of different manufacturing process technologies such as casting process, powder metallurgy, hot extrusion on mechanical properties.

scholarly journals Fabrication of Carbon Nanotubes and Rare Earth Pr Reinforced AZ91 Composites by Powder Metallurgy

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Ning Li ◽  
Hong Yan ◽  
Qingjie Wu ◽  
Zeyu Cao
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Powder Metallurgy ◽  
Extrusion Direction ◽  
Milled Powder ◽  
Hot Extrusion ◽  
Interfacial Bonding ◽  
Tensile Fracture ◽  
Az91 Alloy ◽  
The Matrix

AbstractIt can be known from a large number of research results that improving the dispersibility of CNTs can effectively optimize the mechanical properties of the corresponding metal matrix composites. However, the crucial issue of increasing the bonding of CNTs and the matrix is still unsolved. In this paper, a novel method was developed to increase interfacial bonding strength by coating titanium oxide (TiO2) on the surface of CNTs. The rare earth Pr and TiO2@CNTs-reinforced AZ91matrix composites were successfully fabricated by powder metallurgy. Hot press sintering and hot extrusion of the milled powder was performed. After hot extrusion, the influence of TiO2@CNTs on the microstructure and mechanical properties of the composites were investigated. The results showed that the coating process can improve the distribution of CNTs in Mg alloy. The CNTs refined the grains of the matrix, and the CNTs were presented throughout the extrusion direction. When the TiO2@CNTs content was 1.0 wt.%, the yield strength (YS), ultimate tensile strength (UTS), and elongation of the alloy attained maximum values. The values were improved by 23.5%, 82.1%, and 40.0%, respectively, when compared with the AZ91 alloy. Good interfacial bonding was achieved, which resulted in an effective tensile loading transfer at the interface. CNTs carried the tensile stress and were observed on the tensile fracture.

The Effect of Nano-Graphite Particle to the Friction and Wear Performance of Al-Mg Matrix Composite Material

2012 ◽  
Vol 189 ◽  
pp. 197-200 ◽  
Author(s):  
Shi Ying Tang ◽  
Xiao Xin Liu ◽  
Ying Rui Lin ◽  
Chao Wen
Keyword(s):  
Composite Material ◽  
Powder Metallurgy ◽  
Friction Coefficient ◽  
Abrasion Resistance ◽  
Graphite Particle ◽  
Friction And Wear ◽  
Wear Performance ◽  
Pressing Method ◽  
The Matrix ◽  
Mg Melt

In this paper, with the combination of powder metallurgy and hot pressing method, the nano-graphite Al-Mg composite material was made. This method succeeds in solving the difficulty that graphite particle directly melted with Al-Mg melt, which investigates the amount of nano-graphite’s impact on the abrasion resistance of Al-Mg composite material. The result shows that nano-graphite particle easily to scattered in the matrix when the nano-graphite particle amounts to 1﹪ which can decrease the friction coefficient of composite material. But the material of wear extent increases accordingly along with the increase of the content of nano-graphite.

Effect of High Temperature on Wear Behavior of Stir Cast Aluminium/Boron Carbide Composites

2020 ◽  
Vol 22 (4) ◽  
pp. 1031-1046
Author(s):  
X. Canute ◽  
M. C. Majumder
Keyword(s):  
High Temperature ◽  
Wear Rate ◽  
Boron Carbide ◽  
Wear Behavior ◽  
Base Alloy ◽  
Weight Fraction ◽  
Sliding Velocity ◽  
Wear Properties ◽  
High Temperature Wear ◽  
The Matrix

AbstractThe need for development of high temperature wear resistant composite materials with superior mechanical properties and tribological properties is increasing significantly. The high temperature wear properties of aluminium boron carbide composites was evaluated in this investigation. The effect of load, sliding velocity, temperature and reinforcement percentage on wear rate was determined by the pin heating method using pin heating arrangement. The size and structure of base alloy particles change considerably with an increase of boron carbide particles. The wettability and interface bonding between the matrix and reinforcement enhanced by the addition of potassium flurotitanate. ANOVA technique was used to study the effect of input parameters on wear rate. The investigation reveals that the load had higher significance than sliding velocity, temperature and weight fraction. The pin surface was studied with a high-resolution scanning electron microscope. Regression analysis revealed an extensive association between control parameters and response. The developed composites can be used in the production of automobile parts requiring high wear, frictional and thermal resistance.

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/

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