Squeeze casting of SiCp/Al-alloy composites with various contents of reinforcements

2002 ◽  
Vol 17 (2) ◽  
pp. 376-385 ◽  
Author(s):  
Liang-Guang Chen ◽  
Kung-Hsien Shue ◽  
Shou-Yi Chang ◽  
Su-Jien Lin

Aluminum matrix composites reinforced with various contents and sizes of silicon carbide particles (SiCp) were fabricated by squeeze casting. A lower melting point AA A383 aluminum alloy (A383 Al) was squeezed into the higher melting point SiCp/pure aluminum (SiCp/pure Al) and SiCp/AA 6061 aluminum alloy (SiCp/6061 Al) preforms. The volume percents of the ceramic reinforcements were effectively lowered from traditional 50 to 8–25 vol% by the addition of pure Al and 6061 Al powders in the preforms. The SiC particles uniformly distributed within the matrices, and no pore was found in these composites. The growth of silicon precipitates in A383 Al alloys was limited by the addition of the aluminum alloy powders and SiC particles, and the tensile properties of the alloys were effectively enhanced by the refinement of the silicon precipitates. The tensile strengths and elongations of the SiCp/pure Al/A383 Al and SiCp/6061 Al/A383 Al composites were both better than those of the A383 Al alloy. The T6-treated 12-μm SiCp/6061 Al/A383 Al composite exhibited the highest tensile strength of 301 MPa.

Coatings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 41
Author(s):  
Ainhoa Riquelme ◽  
Pilar Rodrigo ◽  
María Dolores Escalera-Rodriguez ◽  
Joaquin Rams

Ceramic-reinforced metal matrix composites are known for their high wear resistance. A coating based on these materials would be helpful to improve the wear behavior of aluminum alloys. Laser cladding has been used to deposit a coating consisting of an aluminum alloy reinforced with SiC particles on an AA6082 aluminum alloy. Laser cladding is a very energetic technique that causes the SiC particles to react with the molten aluminum to form Al4C3, which degrades the particles and reduces the properties of the coating. The formation of this detrimental compound was successfully achieved with the addition of Silicon and Titanium to the composite matrix. The microstructures of the newly developed material were characterized and the wear behavior was studied under dry sliding conditions on a pin-on-disc tribometer. The relationship between the microstructure and wear behavior was identified. The absence of Al4C3 in the Al40Si/SiC and Al12Si20Ti/SiC coatings’ microstructures resulted in an abrasion mechanism instead of a delamination mechanism. The wear behavior changed along the sliding distances. During the first 200 m of sliding distances, the wear rate of all coatings was lower than the uncoated one due to their higher microhardness. For longer sliding distances, the wear resistance of the uncoated AA6082 was higher than the coated ones due to the formation of a lubricant oxide layer on the AA6082 worn surface. For 1000 m of wear distances, the wear behavior was different for each coating. The wear rate of the Al12Si/SiC coating continued growing due to the delamination mechanism and the presence of Al4C3 that acted as starting crack points. The wear rate of the Al40Si/SiC coating decreased due to the formation of a thin, superficial oxide layer. The wear rate of the Al12SiTi/SiC progressively decreased along the sliding distance to below the substrate wear rate.


2016 ◽  
Vol 256 ◽  
pp. 81-87 ◽  
Author(s):  
Ju Fu Jiang ◽  
Ying Wang ◽  
Shou Jing Luo

Semisolid slurries of 7075 aluminum matrix composite reinforced with nano-sized SiC particles were fabricated by ultrasonic assisted semisolid stirring (UASS) method. Rheoforming and thixoforming of typical cylindrical parts were investigated. The results show that high-quality semisolid slurries with spheroidal solid grain of 38 µm were fabricated by UASS. The nano-sized SiC particles were dispersed uniformly due to transient cavitation and acoustic streaming of ultrasonic wave and high and controllable viscosity of semisolid slurry. Typical cylindrical composite parts with good surface quality and complete filling were rheoformed and thixoformed successfully. Ultimate tensile strength (UTS) of the rheoformed and thixoformed composite parts are enhanced due to addition of nano-sized SiC particles. However, elongation decreased as compared to those of the matrix parts. Maximum UTS of 550 MPa was achieved in the thixoformed composite part with T6 treatment. Increase of dislocation density around the reinforcement particles leads to improvement of the strength and wear resistance of the composite.


Author(s):  
R. GANESH ◽  
M.S. AZHAKESH ◽  
C. BALACHANDRAN ◽  
K. CHANDRASEKARAN

Aluminum matrix composites refer to the class of light weight high performance aluminum centric material systems. The unique tailorability of the composite materials for the specific requirements makes these materials more popular in a variety of applications such as aerospace, automotive (pistons, cylinders, liners, bearings), and structural components, resulting in savings of material and energy. In this project, fabrication of Aluminum MMC by liquid metallurgy route (Squeeze Casting) is discussed in detail. The mechanical properties of 6082 aluminum alloy discontinuously – reinforced with fine particulates of SiCp reinforcement and solutionising time during heat treatment of the composite on hardness, density and impact strength have been evaluated. The cardinal reasons behind the variation in the hardness and impact strength have been discussed.


Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 673
Author(s):  
Ainhoa Riquelme ◽  
Pilar Rodrigo ◽  
María Dolores Escalera-Rodríguez ◽  
Joaquín Rams

Aluminum matrix composites reinforced with silicon carbide particles (SiCp) were deposited by laser cladding on AA6082 aluminum alloy. Different compositions of the matrix of the composites coating were used and different amounts of Si and Ti were added to a base of Al-12Si in order to control the reactivity between molten aluminum and SiCp during laser cladding. The corrosion behavior of the coatings deposited was evaluated in 3.5 wt.% NaCl solution using gravimetric analyses and electrochemical polarization tests. The corrosion products observed were Al(OH)3 and Al2O3, and they formed a layer that limited the evolution of corrosion. However, the presence of discontinuities in it reduced the corrosion resistance of the coating. The corrosion mechanisms were different depending on the coating composition. The addiction of Ti to the alloy allowed for better corrosion behavior for the composite coating than that of the aluminum substrate.


2014 ◽  
Vol 633 ◽  
pp. 117-120
Author(s):  
Jing Liang ◽  
Zhao Hui Huang ◽  
Kai Chen ◽  
Xiao Chao Li ◽  
Ming Hao Fang ◽  
...  

The performance and phase behavior of Quartz - Aluminum Matrix Composites at different temperatures were studied. Quartz aluminum matrix composites were prepared by powder metallurgy method. At the temperature that was less than 660.4°C(the melting point of aluminum), a portion of quartz was happened decomposition and revivification to silicon, most aluminum still existed in the form of metal aluminum. All quartz were happened at the temperature that was higher than 660.4°C. When the temperature is 700°C, the compressive strength of S5(added 40% quartz) is up to 46.02MP. The higher the value of compressive strength was, the less the amount of quartz were happened decomposition. At the temperature more than the melting point of aluminum, Quartz was revivification to silicon, aluminum is oxidized to Al2O3. When the amount of silica exceeded 10%, the mechanical properties of composites declined consequently.


2017 ◽  
Vol 52 (1) ◽  
pp. 123-134 ◽  
Author(s):  
Mohammad Senemar ◽  
Behzad Niroumand ◽  
Ali Maleki ◽  
Pradeep K Rohatgi

In this study, in situ aluminum matrix composites were synthesized through pyrolysis of high temperature vulcanization silicone in commercially pure aluminum melt. For this purpose, 1 to 4 wt% of high temperature vulcanization silicone was added to a vortex of molten aluminum at 750℃ and the resulting slurries were cast in steel dies. Microstructure, hardness, and tensile properties of the as-cast samples were examined at ambient and high temperatures. The results revealed the in situ formation and distribution of reinforcement particles in the matrix. Energy-dispersive X-ray analysis indicated that the formed reinforcement particles consisted of O and Si elements. This confirms the in situ reinforcement formation by pyrolysis of high temperature vulcanization silicone in the melt. The size of the in situ formed particles was mostly in the range of 200–2000 nm. It was shown that the composites synthesized by the addition of 4 wt% high temperature vulcanization had the highest mechanical properties both at ambient and high temperatures. Room temperature hardness, tensile strength, and yield strength of this sample were increased by about 50%, 23%, and 19% compared to the monolithic sample, respectively.


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