EFFECT OF THIXOFORMING ON THE WEAR PROPERTIES OF AL-SI-CU ALUMINUM ALLOY

2017 ◽  
Vol 79 (5-2) ◽  
Author(s):  
Khaled Salem Alhawari ◽  
Mohd Zaidi Omar ◽  
Mariyam Jameelah Ghazali ◽  
Mohd Shukor Salleh ◽  
Mohammed Naser Abdulrazaq

In this study a hypoeutectic Al-6Si-3Cu aluminium alloy was synthesized using two different routes: the thixoforming process and the conventional mould casting process. The microstructural features, hardness and wear behavior of thixoformed alloy have been evaluated and compared with that of as-cast alloy. Cooling slope method was used to produce the non-dendritic microstructure feedstock for thixoforming. Thixoforming was carried out at 50% liquid fraction. The dry sliding wear behaviour of the produced alloys was investigated under two loads; namely, 10 and 50 N and 1m/s sliding speed for 9 km sliding distance. The thixoformed alloy exhibited globular primary phase morphology with fine and uniform distributed Si and intermetallic particles. On the contrary, dendritic primary phase, coarse flaky silicon particles and segregated microstructure has been observed in conventional cast alloy. Thixoformed alloy exhibited improvement in the wear resistance in comparison to the conventional cast alloy, which may be attributed to the microstructural enhancement resulting in improved hardness. The thixoformed samples displayed lower volume loss of ~16.20 mm3 and ~42.40 mm3 at loads of 10 and 50 N respectively compared with that of conventional cast samples. On the basis of observations and analyses on the wear rates and worn surfaces, the wear mechanism of the alloys was dominantly controlled by abrasive, adhesive and minor delamination.

2019 ◽  
Vol 285 ◽  
pp. 63-68 ◽  
Author(s):  
Mnel A. Abdelgnei ◽  
M. Zaidi Omar ◽  
Mariyam Jameelah Ghazali

Earlier work has shown that Al-5.7Si-2Cu-0.3Mg aluminium alloy is suitable for thixoforming process. Here, the dry sliding wear behaviour of the alloy, in the as-cast and thixoformed conditions were investigated. The cooling slope technique was used to produce the alloy with globular microstructure for the thixoforming process. Both the thixoformed and cast samples were subjected to T6 heat treatments prior to the wear tests. The tests were carried out using a pin-on-disc tribometer, against a hardened M2 tool steel disc of 62 HRC at different loads, under dry sliding conditions at fixed sliding speed and sliding distance of 1 m.s–1 and 5 km respectively. The microstructural response, worn surfaces were thoroughly and carefully examined using various methods such as scanning electron microscopy, energy dispersive spectroscopy, and differential scanning calorimetry. The density of the heat treated thixoformed alloys showed significant increase in the hardness property, among others, due to its reduced porosity. Their wear test results also observed that the weight loss of materials increase with an increase in the input load and the sliding distance for all samples. However, the as-cast alloy displayed higher wear rate compared with the thixoformed alloys. In general, the wear mechanisms showed a mixture of abrasive, oxidative and delamination wear (mild wear) at low applied loads and mainly an adhesive (severe wear) at high applied loads.


Aluminum Composite are widely used in aviation and automotive industries because it is light in weight hence it reduces the fuel consumption and improves the energy efficiency. The present work deals with preparing Aluminum-based particle reinforced composite fabricated through Stir Casting Process wherein Sic along with Graphite are used as reinforcements which has improved mechanical properties with reduction in weight. Impact toughness, hardness along with wear property of the fabricated composite samples were tested and compared with Al 5052 Cast Alloy based on ASTM Standard. From the testing, we can conclude that Impact toughness, Hardness and wear properties of Al 5052 base alloy is considerably increased due to the addition of particulate reinforcements. And also there is not much studies reported on the influence of Sic and Graphite as reinforcement on Impact toughness, hardness along with Wear behavior of Al 5052 alloy. So the objective of the current work is to fabricate Al 5052 base alloy reinforced with particulate composite by stir casting process and to study the Impact toughness, hardness, and microstructure along with wear behavior of the fabricated composites.


2006 ◽  
Vol 317-318 ◽  
pp. 351-354
Author(s):  
Mark I. Jones ◽  
Kiyoshi Hirao ◽  
Hideki Hyuga ◽  
Yukihiko Yamauchi

The effects of microstructure and composition on the wear properties of Lu sialon ceramics have been studied under dry sliding conditions through block-on-ring wear tests. Microstructural and compositional effects on wear behaviour were studied by producing both equiaxed and elongated α sialons through the incorporation of additional oxides to promote extended liquid formation and grain growth, and by producing α / β composite materials with elongated β grains. The wear response of the materials is discussed in terms of the dominant wear mechanism under different experimental conditions. Under higher loads, where fracture dominates, materials with improved mechanical properties show better wear resistance and both the composite materials and the elongated α sialons showed lower wear rates than the equiaxed materials due to the elongated grain microstructures. Under low normal loads, fracture does not occur and the dominant wear mechanism is thought to be tribochemically assisted wear. Under these conditions, the equiaxed materials had better wear resistance than the composites, and the Lu-α sialon showed an order of magnitude lower wear rate than an equivalent Y-α sialon, thought to be due to better oxidation resistance and improved refractory nature afforded through the use of the smaller radius cation. The elongated Lu-α sialons under these low load conditions showed wear resistance that was to some extent dependent on the composition of the additional liquid phase, with high SiO2 contents leading to higher wear rates.


2011 ◽  
Vol 471-472 ◽  
pp. 1165-1170 ◽  
Author(s):  
H.R. Jafari Nodooshan ◽  
M. Emamy ◽  
N. Nemati ◽  
A. Bahrami

This study was undertaken to investigate the effect of different concentrations of Yttrium (0.1, 0.3, 0.5, 1.0 wt.%) and heat treatment on the microstructure, hardness and wear resistance of an in-situ cast composite (Al-15%Mg2Si ). The microstructural study of the composite before and after solution and ageing showed both primary and secondary Mg2Si phases in all specimens and intermetallics containing Y (Al2Y) were visible after Solution at 520 °C for 4 hours. Hardness measurement demonstrates that the addition of Y increases the hardness gradually but a reduction in the hardness of heat treated specimen’s occurs with the addition of Y ( 0.5%Y).Wear tests were performed using a pin on disk apparatus. The MMCs were rubbed against a carbon steel pin under a load of 10 and 20 N at a sliding velocity of 0.1 ms−1; track length of 1500 m. The degree of improvement in dry sliding wear resistance brought about by Y addition is strongly dependent on the formation of Yttrium rich intermetallic phases as well as heat treatment influence and the wear behavior determined through the precise measurement of weight loss of the samples and wear rates. Worn surfaces were analyzed by scanning electron microscopy (SEM).


2015 ◽  
Vol 830-831 ◽  
pp. 358-361 ◽  
Author(s):  
D.G. Sondur ◽  
D.M. Goudar ◽  
D.G. Mallapur ◽  
G.B. Rudrakshi

In the present investigation, microstructural characteristics and dry sliding wear behaviour of T6 heat treated conventionally cast Al-25Mg2Si-2Cu alloy have been discussed. The as cast alloy was subjected to solutionizing at 500°C for 5h and isothermal aging treatment at 190°C for different aging times. The micro structural characterization was studied using Scanning Electron Microscope with EDS analysis. The microstructure of as cast alloy consists of intermetallics of coarse block like sharp edged β-(Mg2Si), θ-(Al2Cu) and Q-(Al-Mg-Cu-Si) in the form of Chinese scripts and needles distributed randomly in the Al-matrix. The microstructure of heat treated alloy shows spheroidization of β phase and fine precipitation of θ-(Al2Cu) and Q phases. The dry sliding wear test was carried out using pin-on-disc machine. Age hardened alloy exhibits high wear resistance and minimum coefficient of friction over the entire range of applied loads and sliding velocities. Furthermore, high wear resistance was observed in the under aged condition compared to over ageing conditions.


2021 ◽  
Vol 59 (12) ◽  
pp. 870-879
Author(s):  
Kyoung-Wook Kim ◽  
Min-Seok Baek ◽  
Kwangjun Euh ◽  
Kee-Ahn Lee

Al 7075 alloy was manufactured using the twin-roll strip casting (TRC) process, and the mechanical and wear properties of the fabricated TRC process were investigated. To compare the properties of the alloy manufactured by TRC, another Al 7075 alloy was fabricated by conventional direct chill (DC) casting as a comparative material. Based on initial microstructure observations, the Al 7075 alloy manufactured by the DC process showed relatively elongated grains compared to the Al 7075 alloy by TRC process. In both alloys, η(MgZn2) phases were present at the grain and grain boundaries. In the Al 7075 alloy manufactured by the DC process, the η(MgZn2) phases were coarse with a size of ~86 nm and were mainly concentrated in the local area. However, the Al 7075 alloy manufactured by TRC had relatively fine η(MgZn2) phases size of ~40 nm, and they were evenly distributed throughout the matrix. When the mechanical properties of the two alloys were compared, the TRC process showed higher hardness and strength properties than the DC process. In room temperature wear test results, the TRC process exhibited lower weight loss and wear rates compared to the DC process at all wear loads. In other words, the TRC process resulted in relatively superior wear resistance properties compared to the conventional DC process. The wear behavior of both alloys changed from abrasive wear to adhesive wear as the wear load increased. However, the TRC process maintained abrasive wear up to higher loads. Based on the above results, a correlation between the microstructure and wear mechanism of the Al 7075 alloy manufactured by TRC is also suggested.


Author(s):  
H. Sh. Hammood ◽  
S. S. Irhayyim ◽  
A. Y. Awad ◽  
H. A. Abdulhadi

Multiwall Carbon nanotubes (MWCNTs) are frequently attractive due to their novel physical and chemical characteristics, as well as their larger aspect ratio and higher conductivity. Therefore, MWCNTs can allow tremendous possibilities for the improvement of the necessarily unique composite materials system. The present work deals with the fabrication of Cu-Fe/CNTs hybrid composites manufactured by powder metallurgy techniques. Copper powder with 10 vol. % of iron powder and different volume fractions of Multi-Wall Carbon Nanotubes (MWCNTs) were mixed to get hybrid composites. The hybrid composites were fabricated by adding 0.3, 0.6, 0.9, and 1.2 vol.% of MWCNTs to Cu- 10% Fe mixture using a mechanical mixer. The samples were compressed under a load of 700 MPa using a hydraulic press to compact the samples. Sintering was done at 900°C for 2 h at 5ºC/min heating rate. The microscopic structure was studied using a Scanning Electron Microscope (SEM). The effect of CNTs on the mechanical and wear properties, such as micro-hardness, dry sliding wear, density, and porosity were studied in detail. The wear tests were carried out at a fixed time of 20 minutes while the applied loads were varied (5, 10, 15, and 20 N). SEM images revealed that CNTs were uniformly distributed with relative agglomeration within the Cu/Fe matrix. The results showed that the hardness, density, and wear rates decreased while the percentage of porosity increased with increasing the CNT volume fraction. Furthermore, the wear rate for all the CNTs contents increased with the applied load.


2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Mahsa Ebrahimi ◽  
Abbas Zarei-Hanzaki ◽  
A. H. Shafieizad ◽  
Michaela Šlapáková ◽  
Parya Teymoory

The present work was primarily conducted to study the wear behavior of as-received and severely deformed Al-15%Mg2Si in situ composites. The severe plastic deformation was applied using accumulative back extrusion (ABE) technique (one and three passes). The continuous dynamic recrystallization (CDRX) was recognized as the main strain accommodation and grain refinement mechanism within aluminum matrix during ABE cycles. To investigate the wear properties of the processed material, the dry sliding wear tests were carried out on both the as-received and processed samples under normal load of 10 and 20 N at room temperature, 100 °C, and 200 °C. The results indicated a better wear resistance of processed specimens in comparison to the as-received ones at room temperature. In addition, the wear performance was improved as the ABE pass numbers increased. These were related to the presence of oxide tribolayer. At 100 °C, the as-received material exhibited a better wear performance compared to the processed material; this was attributed to the formation of a work-hardened layer on the worn surface. At 200 °C, both the as-received and processed composites experienced a severe wear condition. In general, elevating the temperature changed the dominant wear mechanism from oxidation and delamination at room temperature to severe adhesion and plastic deformation at 200 °C.


Author(s):  
Santosh Vitthal Bhaskar ◽  
Hari Narayan Kudal

In the present article, samples made of AISI 4140 steel, pre-treated with plasma nitriding (PN), and coated with different coatings like Titanium Carbonitride (TiCN), Aluminium Chromium Nitride (AlCrN), using Physical Vapor Deposition (PVD) technique, were investigated in terms of their microhardness, surface roughness, and dry sliding wear behaviour. Wear tests were performed with a pin-on-disc machine. Coatings were deposited on plasma nitrided samples. The wear behaviour, and wear mechanisms of TiCN- and AlCrN-coated, PN treated AISI 4140 specimens were investigated using a field emission Scanning Electron Microscope (SEM), equipped with an Energy Dispersive X-ray (EDX) analyzer. An SEM was used to study the surface morphology of the worn surfaces. Also, adhesion tests were conducted to investigate the adhesion quality of the coated specimens. The results of the investigation showed improved wear properties. Furthermore, the compound layer formed during nitriding was found to act as an intermediate hard layer, leading to superior sliding wear properties.


2021 ◽  
Vol 118 (6) ◽  
pp. 614
Author(s):  
Chellamuthu Ramesh Kumar ◽  
Subramanian Baskar ◽  
Ganesan Ramesh ◽  
Pathinettampadian Gurusamy ◽  
Thirupathy Maridurai

In this research, investigations were carried out on Al6061 base alloy with the changing weight percentage of silicon carbide (SiC) and boron carbide (B4C) with keeping the amount of talc constant. The main objective of this present study was to improve the wear resistance of aluminum alloy using SiC/B4C/talc ceramic particles using stir-casting technique and how the eco-friendly talc content influencing the solid lubricity during the abrasion process. The experiments were conducted via orthogonal array of L27 using Taguchi’s method. The optimum value along with the coefficient of friction was obtained on the basis of grey relational equations and ANOVA, which helped in analysis of most influential input parameters such as applied load, sliding speed, sliding distance and percentage of reinforcement. Conformation tests were performed for the purpose of validation of the experimental results. The specimens were analyzed using scanning electron microscope (SEM) with EDX for micro structural studies. The SiC, B4C and talc presence in the composite helped to improve the mechanical properties, according to the results. The presence of solid lubricant talc as reinforcement to the aluminum hybrid composite reduced the wear properties and decreased the co-efficient friction. These wear resistance improved aluminum metal matrix composites could be used in automobile, defense and domestic applications where high strength and wear resistance required with lesser specific weight.


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