The Corrosion Behaviour of Mg Alloy AZ91D/TiCp Metal Matrix Composite

2005 ◽  
Vol 488-489 ◽  
pp. 705-708 ◽  
Author(s):  
Suqiu Jia ◽  
Shu Sheng Jia ◽  
Guangping Sun ◽  
Jun Yao
Keyword(s):  
Metal Matrix ◽  
Corrosion Behaviour ◽  
Galvanic Corrosion ◽  
General Corrosion ◽  
Az91d Alloy ◽  
Alloy Matrix ◽  
Electrochemical Tests ◽  
Alloy Az91d ◽  
The Matrix ◽  
Carbide Particles

The corrosion of a magnesium-based MMC, comprising a AZ91D alloy matrix and 5 vol% titanium carbide particles has been studied in saline environments, using immersion and electrochemical tests. Corrosion was localized initially and developed subsequently into general corrosion , the local corrosion rate of AZ91D/TiCp being faster than diecast AZ91D due to the formation of less protective corrosion products. Galvanic corrosion for AZ91D/TiCp, due to coupling of the matrix and reinforcement, was more severe than diecast AZ91D.

Mechanical characterization of LM25 alloy matrix composite reinforced with boron carbide

2021 ◽  
pp. 002199832110055
Author(s):  
Zeeshan Ahmad ◽  
Sabah Khan
Keyword(s):  
Tensile Strength ◽  
Boron Carbide ◽  
Mechanical Characterization ◽  
Stir Casting ◽  
Surface Mapping ◽  
Alloy Matrix ◽  
Casting Technique ◽  
The Matrix ◽  
Carbide Particles

Alumnium alloy LM 25 based composites reinforced with boron carbide at different weight fractions of 4%, 8%, and 12% were fabricated by stir casting technique. The microstructures and morphology of the fabricated composites were studied by scanning electron microscopy and energy dispersive spectroscopy. Elemental mapping of all fabricated composites were done to demonstrate the elements present in the matrix and fabricated composites. The results of microstructural analyses reveal homogenous dispersion of reinforcement particles in the matrix with some little amount of clustering found in composites reinforced with 12% wt. of boron carbide. The mechanical characterization is done for both alloy LM 25 and all fabricated composites based on hardness and tensile strength. The hardness increased from 13.6% to 21.31% and tensile strength 6.4% to 22.8% as reinforcement percentage of boron carbide particles increased from 0% to 12% wt. A fractured surface mapping was also done for all composites.

Manufacture of Continuous Metal Matrix Composite Strip Reinforced by Particulate Materials from the Semisolid Processing

2019 ◽  
Vol 285 ◽  
pp. 189-196
Author(s):  
Antonio de Pádua Lima Filho ◽  
Bruno Katsuyoshi Silama Ueda ◽  
Tales Paschoalino de Castro ◽  
Rodrigo Alessandro Nunes de Oliveira
Keyword(s):  
Metal Matrix ◽  
Surface Defects ◽  
Cast Alloy ◽  
Eutectic Structure ◽  
Nucleation Agent ◽  
Alloy Matrix ◽  
Cooling Slope ◽  
Α Phase ◽  
The Matrix ◽  
Graphite Nanoparticles

Strip casting is a new method of producing metal matrix composites. Two-roll melt dragged processing (TRMD-ing) and single-roll melt dragged processing (SRMD-ing) methods were used to study the manufacture of 2-mm-thick composite strips by using PbSn (≈ 11.3 g/cm3) eutectic alloy matrix reinforced with iron (≈ 7.86 g/cm3) powder (≈ 70 μm) at a rate of 0.3 m/s. The metallic powder stored in the feed hopper (≈ 90 g) was pushed during the pouring operation of the cast alloy (≈ 4 kg) at 260 oC on the cooling slope to produce a mixture of metallic slurry and particles to feed the nozzle to be dragged by the lower roll. Various surface defects occurred during processing, such as the failure of the powder particle to be embedded in the matrix by SRMD-ing with and without stirrer into the nozzle, and the rolling up of the strip into the nozzle by TRMD-ing. Graphite nanoparticles formed inside the α-Pb grain revealed a complicate eutectic structure in both the processing methods. The colloidal graphite used to coat the crucible, cooling slope, and nozzle could act as a nucleation agent for preferential centre segregation in the α-Pb grain. This suggests that the graphite nanoparticles functioned as nucleation points in the lead-rich α phase. Thus, another type of composite was formed in the presence of graphite nanoparticles within the lead-rich α-phase surrounded by β-Sn. An electron probe microanalysis and scanning electronic microscopy were used to investigate the composition and distribution and identify the different phases. Several types of particulate reinforcements may be added to the matrix to obtain composites for mechanical, electronic, and magnetic applications using these technologies.

Corrosion of AZ91 - Influence of the β-Phase Morphology

2009 ◽  
Vol 618-619 ◽  
pp. 473-478 ◽  
Author(s):  
M.C. Zhao ◽  
Peter J. Uggowitzer ◽  
M. Liu ◽  
Patrik Schmutz ◽  
G. Song ◽  
...  
Keyword(s):  
Corrosion Behaviour ◽  
Galvanic Corrosion ◽  
Mg Alloys ◽  
Model Alloy ◽  
Second Phase ◽  
Surface Films ◽  
Β Phase ◽  
The Matrix ◽  
Theoretical Phase Diagram ◽  
Multi Phase

The influence of the microstructure, particularly the morphology of the β phase, on the corrosion of Mg alloys has been studied using AZ91 as a model alloy and compared with the corrosion of pure magnesium, used as a standard for comparison. The concentration of the impurity element Fe was below the limit evaluated from theoretical phase diagram construction. Corrosion was measured using hydrogen evolution measurements and some polarization measurements. Corrosion behaviour was characterized for four different microstructures produced by heat treatment of as-cast AZ91: namely (i) as-cast, (ii) homogenization anneal (for 5h and 10h at 380°C), (iii) solid solution and (iv) solution treated and aged. The influence of microstructure can be understood from the interaction of the following three factors: (i) the surface films, (ii) micro-galvanic corrosion acceleration dependant on the amount and distribution of the second phase (the  phase in AZ91) and (iii) the second phase can act as a corrosion barrier and hinder corrosion propagation in the matrix, if the second phase is in the form of a continuous network. It is expected that these factors are important for all multi-phase Mg alloys because all known second phases have corrosion potentials more positive than that of the -phase. The electrochemical measurements did not give good values for the corrosion rate in agreement with the literature.

scholarly journals The Study of the Corrosion Behavior of Zinc-Aluminum Alloy Matrix Composite Reinforced with Nanosilica Produced by Stir Casting

2020 ◽  
Vol 38 (3A) ◽  
pp. 375-382
Author(s):  
Fatima A. Adnan ◽  
Niveen J. Abdul Kader ◽  
Mohammed S. Hamza
Keyword(s):  
Metal Matrix ◽  
Dendritic Structure ◽  
Stir Casting ◽  
Zinc Alloy ◽  
Al Alloy ◽  
Unreinforced Alloy ◽  
Alloy Matrix ◽  
Weight Percentage ◽  
Reinforcing Particles ◽  
The Matrix

In this investigation, Zn-Al alloy metal-matrix nano composites that reinforced via various weight percentages (2%, 4%, 6%, and 8%) of nanosilica (SiO2) particles were fabricated applying the technique of stir casting. Behaviors of the corrosion of the unreinforced alloy and reinforced composites were measured utilizing a potentiostat test in a (3.5 wt.% NaCl) salt solution. The optical microscopy was employed to investigate the surface microstructure of the composite. Microstructure analysis manifested that the uniform distributions of the reinforcing particles in the composites are alike, consisting of a dendritic structure of the zinc alloy matrix with an excellent reinforcing particles steady dispersion. The improved results of the corrosion resistance for the metal matrix composites showed an excellent resistance to corrosion than the matrix in the (3.5 wt.% NaCl) solution. Raising the weight percentage of the reinforcement particulates of nansilica (SiO2) reduced the composites rate of corrosion.

Microstructural evolution and corrosion behaviour of friction stir-processed QE22 magnesium alloy

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ankur Kumar ◽  
F. Khan MD ◽  
Sushanta Kumar Panigrahi ◽  
Gajanan P. Chaudhari
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behaviour ◽  
Galvanic Corrosion ◽  
Point Of View ◽  
Second Phase ◽  
Friction Stir ◽  
Ultrafine Grained ◽  
Second Phase Particles ◽  
Before And After ◽  
The Matrix

Abstract Effect of microstructural changes after friction stir processing (FSP) on the corrosion behaviour of rare earth containing QE22 magnesium alloy is studied. FSP produced ultrafine-grained α-Mg matrix and refined the Mg12Nd precipitates whereas Mg12Nd2Ag precipitates got dissolved in the matrix. Although its hardness increased from 76 to 90 VHN, the FSPed alloy displayed inferior corrosion resistance in 3.5 wt% NaCl solution. This is attributed mainly to the iron contamination from FSP and presence of refined second phase particles which work as active cathodic sites. The role of distributed Mg12Nd precipitates before and after FSP is analysed from micro galvanic corrosion point of view.

Influence of Particles Type and Shape on the Corrosion Resistance of Aluminium Hybrid Composites

2012 ◽  
Vol 191 ◽  
pp. 81-87 ◽  
Author(s):  
Anna J. Dolata ◽  
Maciej Dyzia ◽  
Witold Walke
Keyword(s):  
Corrosion Resistance ◽  
Hybrid Composites ◽  
Corrosion Behaviour ◽  
Matrix Alloy ◽  
Combustion Engines ◽  
Alloy Matrix ◽  
Nacl Concentration ◽  
The Matrix ◽  
Aluminium Alloy Matrix

AMCs due to good thermal and tribological properties, they are applied as the material for: pistons in modern combustion engines, drive shafts, shock absorber cylinders and brake nodes. Heavy-duty operation, especially under tribological conditions, frequently in corrosive environment, requires knowledge on their corrosion resistance. This paper presents the initial results of the research on susceptibility of aluminium alloy matrix composite material reinforced by SiC particles and mixture of SiC+C particles to corrosion. The purpose of the research was to determine the influence of reinforcing phases, their type and shape on corrosion behaviour in a typical corrosion environment, with low NaCl concentration, in relation to the matrix alloy. Determination of corrosion resistance of Al/SiC+C hybrid composite is a new issue and falls within the field of interest of the authors of this article.

scholarly journals Corrosion Behaviour of Heat-Treated Aluminum-Magnesium Alloy in Chloride and EXCO Environments

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
S. O. Adeosun ◽  
O. I. Sekunowo ◽  
S. A. Balogun ◽  
V. D. Obiekea
Keyword(s):  
Corrosion Behaviour ◽  
Chemical Constituents ◽  
Electrochemical Techniques ◽  
Galvanic Coupling ◽  
Alloy Matrix ◽  
Heat Treated ◽  
The Matrix ◽  
Corrosion Susceptibility ◽  
Corrosion Simulation ◽  
Aluminum Magnesium Alloy

Machines designed to operate in marine environment are generally vulnerable to failure by corrosion. It is therefore imperative that the corrosion susceptibility of such facilities is evaluated with a view to establishing mechanism for its mitigation. In this study, the corrosion behaviour of as-cast and retrogression-reagion (RRA) specimens of aluminum alloy containing 0.4–2.0 percent magnesium additions in NaCl, FeCl3, and EXCO solutions was investigated. The corrosion simulation processes involved gravimetric and electrochemical techniques. Results show substantial inducement of Mg2Si precipitates at a relatively higher magnesium addition, 1.2–2.0 percent, giving rise to increased attack. This phenomenon is predicated on the nature of the Mg2Si crystals being anodic relative to the alloy matrix which easily dissolved under attack by chemical constituents. Formation of Mg2Si intermetallic without corresponding appropriate oxides like SiO2and MgO, which protect the precipitates from galvanic coupling with the matrix, accentuates susceptibility to corrosion.

scholarly journals Tribological characteristics of Al/SiC/Gr hybrid composites

2018 ◽  
Vol 183 ◽  
pp. 02001 ◽  
Author(s):  
Sandra Veličković ◽  
Slavica Miladinović ◽  
Blaža Stojanović ◽  
Ružica Nikolić ◽  
Branislav Hadzima ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Hybrid Composites ◽  
High Strength ◽  
Tribological Characteristics ◽  
Matrix Composites ◽  
Alloy Matrix ◽  
The Matrix ◽  
Aluminum Metal Matrix Composites

Metal matrix composites (MMCs) are considered as important engineering materials due to their excellent mechanical, as well as tribological properties. When the metal (or alloy) matrix is reinforced with two or more reinforcements, those composites are the so-called hybrid composites. The aluminum metal matrix composites, reinforced with silicon carbide (SiC) and graphite (Gr), are extensively used due to their high strength and wear resistance. The tribological characteristics of such materials are superior to characteristics of the matrix. This research is presenting influence of the load and the graphite and silicon carbide contents the composites’ wear rate and the friction coefficient.

The Production of Cast Metal Matrix Composite by a Modified Stir Casting Method

2012 ◽  
Author(s):  
Jasmi Hashim
Keyword(s):  
Silicon Carbide ◽  
Tensile Strength ◽  
Metal Matrix Composite ◽  
Metal Matrix ◽  
Matrix Alloy ◽  
Stir Casting ◽  
The Matrix ◽  
Silicon Carbide Particles ◽  
Carbide Particles ◽  
Particle Addition

Dalam praktik biasa teknik tuangan kacau, komposit matriks logam dihasilkan dengan cara meleburkan bahan matriks dalam suatu bekas kemudiannya leburan logam ini dikacau dengan kuat untuk membentuk vorteks dan bahan tetulang partikel dimasukkan melalui bahagian tepi vorteks yang telah terbentuk. Daripada satu sudut pandangan pendekatan ini mempunyai kekurangan, yang timbul daripada kaedah memasukkan partikel dan kaedah pengacuan. Semasa penambahan partikel ini dilakukan akan berlaku pemejalan setempat dalam leburan tersebut yang teraruh oleh partikel, dan ini akan meningkatkan kelikatan buburan tersebut. Kaedah penambahan partikel melalui bahagian atas ini juga akan memasukkan udara ke dalam buburan yang muncul sebagai poket udara di antara partikel tersebut. Kadar penambahan partikel ini juga perlu diperlahankan terutamanya apabila terdapat peningkatan pecahan isipadu partikel yang digunakan. Proses ini akan memakan masa yang lama terutamanya untuk produk yang lebih besar. Kajian ini mencadangkan satu pendekatan baru untuk menghasilkan tuangan MMC. Apabila semua bahan dimasukkan ke dalam mengkok grafit dan dipanaskan dalam atmosfera lengai sehingga aloi matriks menjadi lebur dan kemudiannya diikuti dengan tindakan kacauan dua-langkap sebelum penuangan ke dalam acuan, mempunyai kelebihan daripada segi menggalakkan kebolehbasahan di antara partikel silikon karbida dengan aloi A359 aloi matriks. Kejayaan penambahan partikel silikon karbida ke dalam aloi matriks telah menunjukkan bahawa kebolehbasahan di antara partikel silikon karbida, dan sifat mekanikal seperti kekerasan dan kekuatan tegangan adalah setanding dengan data sebelumnya yang dihasilkan oleh penyelidik lain. Kata kunci: Komposit matriks logam; tuangan kacau; kebolehbasahan; kekerasan; kekuatan; penyebaran partikel In a normal practice of stir casting technique, cast metal matrix composites (MMC) is produced by melting the matrix material in a vessel, then the molten metal is stirred thoroughly to from a vortex and the reinforcement particles are introduced through the side of the vortex formed. From some point of view this approach has disadvantages, mainly arising from the particle addition and the stirring methods. During particle addition there is undoubtedly local solidification of the melt induced by the particles, and this increase the viscosity of the slurry. A top addition method also will introduced air into the slurry which appears as air pockets between the particles. The rate of particle addition also needs to be slowed down especially when the volume fraction of the particles to be used increases. This is time consuming for a bigger product. This study propose a new approach of producing cast MMC. When all substances are placed in a graphite crucible and heated in an inert atmosphere until the matrix alloy is melted and then followed by a two–step stirring action before pouring into a mould has advantages in terms of promoting wettability between the silicon carbide particle and the A359 matrix alloy. The success of the incorporation of silicon carbide particles into the matrix alloy showed that the wettability between silicon carbide particles and mechanical properties such as hardness and tensile strength are comparable with previous data produced by other researchers. Keywords: Metal matrix composite; stir casting; wettability; hardness; tensile strength; particle distribution.

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