scholarly journals Reactivity and Microstructure of Al2O3-Reinforced Magnesium-Matrix Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Maher Mounib ◽  
Matteo Pavese ◽  
Claudio Badini ◽  
Williams Lefebvre ◽  
Hajo Dieringa

Performances of metal matrix composites (MMCs) rely strongly on the distribution of particles within the metal matrix but also on the chemical reaction which may occur at the liquid-solid interfaces. This paper presents the chemical reaction between aluminum based particles Al2O3and Al2O3-AlOOH with magnesium alloys matrixes AZ91 and EL21, respectively, and studies the microstructure of these reinforced composites. Different methods such as transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and XRD were used to highlight these chemical reactions and to identify products. Results demonstrate the formation of MgO particles within the matrix for both composites and also the dissolution of aluminum in the eutectic region in the case of EL21.

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5182
Author(s):  
Katarzyna N. Braszczyńska-Malik

In this paper, a summary of investigations of the microstructure of cast magnesium matrix composites is presented. Analyses of the interfaces between the reinforcing particles and the magnesium alloy matrices were performed. Technically pure magnesium and four various alloys with aluminum and rare earth elements (RE) were chosen as the matrix. The composites were reinforced with SiC and Ti particles, as well as hollow aluminosilicate cenospheres. Microstructure analyses were carried out by light, scanning, and transmission electron microscopy. The composites with the matrix of magnesium and magnesium–aluminum alloys with SiC and Ti particles exhibited coherent interfaces between the components. In the composites based on ternary magnesium alloy with Al and RE with Ti particles, a high-melting Al2RE phase nucleated on the titanium. Different types of interfaces between the components were observed in the composites based on the magnesium–rare earth elements alloy with SiC particles, in which a chemical reaction between the components caused formation of the Re3Si2 phase. Intensive chemical reactions between the components were also observed in the composites with aluminosilicate cenospheres. Additionally, the influence of coatings created on the aluminosilicate cenospheres on the bond with the magnesium matrix was presented. A scheme of the types of interfaces between the components is proposed.


2014 ◽  
Vol 591 ◽  
pp. 120-123 ◽  
Author(s):  
B. Vijaya Ramnath ◽  
Chakravarthi Parswajinan ◽  
Chinnadurai Elanchezhian ◽  
S. Venkatesan Pragadeesh ◽  
P. Ravichandra Ramkishore ◽  
...  

Carbon Nanotubes (CNT) are one allotropic form of carbon, which have some unique characteristics that make them a suitable reinforcing agent in various types of composites. CNT reinforced composites are gaining more attention in recent days. Reinforcing with CNT leads to increase in strength without considerable increase in weight. Many metal matrix composites (MMCs) with base metals like aluminium, magnesium, copper, nickel etc., and polymer matrix composites (PMCs) have been fabricated and experimented with CNT as one of their reinforcing agents and corresponding results have been recorded. This paper reviews a few of these recordings on Al and Mg MMCs and also some future development in this field.


2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Ding Hualun

This paper chooses magnesium as the matrix of composite materials, selects carbon fi ber as reinforcement, anddesigns the composite scheme according to the structure and performance of Mg-based composites. The performancecharacteristics and application prospect of fiber-reinforced magnesium matrix composites are introduced. Wait. Inthis paper, the process of preparing carbon fi ber magnesium matrix composites by compression casting method andspray deposition method is designed. The process fl ow chart of these two design schemes is determined by analyzingthe principle of these two kinds of preparation methods, and the specifi c problems of the process are analyzed andsummarized.


2000 ◽  
Vol 6 (5) ◽  
pp. 452-462 ◽  
Author(s):  
Julie M. Cairney ◽  
Robert D. Smith ◽  
Paul R. Munroe

AbstractTransmission electron microscope samples of two types of metal matrix composites were prepared using both traditional thinning methods and the more novel focused ion beam miller. Electropolishing methods were able to produce, very rapidly, thin foils where the matrix was electron transparent, but the ceramic reinforcement particles remained unthinned. Thus, it was not possible in these foils to study either the matrix-reinforcement interface or the microstructure of the reinforcement particles themselves. In contrast, both phases in the composites prepared using the focused ion beam miller thinned uniformly. The interfaces in these materials were clearly visible and the ceramic reinforcement was electron transparent. However, microstructural artifacts associated with ion beam damage were also observed. The extent of these artifacts and methods of minimizing their effect were dependent on both the materials and the milling conditions used.


2012 ◽  
Vol 706-709 ◽  
pp. 687-692
Author(s):  
Li Ming Peng ◽  
Bin Hu ◽  
Wen Jiang Ding

Metal matrix composites reinforced with discontinuous reinforcement (short fiber, whisker or particle) are attractive for applications requiring higher stiffness and strength than traditional alloys. Unlike continuously reinforced composites, where the properties are mainly influenced by fibers, the properties of the discontinuously reinforced composites seem to be influenced more by matrix properties. Most of the discontinuously reinforced composites are based on age-hardenable light alloys, so that aging treatments can be applied to develop the optimum properties of the composites. The aging behavior of discontinuously reinforced composites has been a subject of great interest both from scientific and technological view points. Recently developed NZ30K (Mg-3wt.%Nd-0.5wt.%Zn-0.5wt.%Zr) alloys exhibit higher specific strength at both room and elevated temperatures, better strength and creep resistance than the existing commercial magnesium alloys. Accordingly, this alloy can be considered as a candidate material for potential automobile applications, such as engine blocks and pistons, which experience high service temperature. Its use could save considerable mass weight in powertrain systems. However, low elastic modulus and wear resistance of magnesium alloys limit their widespread applications. Metal matrix composites have been proposed as the feasible and economical solution. The aim of this study is to investigate the effect of alumina fibers on the aging hardening kinetics and age-hardening efficiency of squeeze cast NZ30K/Saffil/15p magnesium matrix composite. The aging behavior has been examined using Vickers, combined with microstructure observation developed during heat treatment by optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).


2019 ◽  
Vol 70 (8) ◽  
pp. 2903-2907
Author(s):  
Ruxandra Elena Dumitrescu ◽  
Ioana Arina Gherghescu ◽  
Sorin Ciuca ◽  
Mariana Ciurdas ◽  
Daniela Alina Necsulescu ◽  
...  

Two magnesium matrix composites reinforced with 3 and 10% Ni-Ti particulates, respectively, were obtained by plasma sintering. The reinforcement material was obtained by grinding a mixture of powders of 68% Ni and 32% Ti atomic percent in a high energy mill for 40 hours. Particulates resulting from mechanical alloying have a partially amorphous and partially nanocrystalline structure, consisting of the following phases: Ni solid solution, Ti2Ni and NiTi (B2) phase. After sintering, both the matrix and the reinforcement material are nanocrystalline and the particulates have a polyphase structure, consisting of Ni(Ti), NiTi (R phase) and Ni4Ti3. The hardness of these composites is superior to the hardness of magnesium matrix composites reinforced with Ni-Ti particulates having 50% Ni / 50% Ti and 32% Ni / 68% Ti chemical compositions obtained under the same conditions and corresponding proportions of reinforcement material.


2007 ◽  
Vol 561-565 ◽  
pp. 945-948 ◽  
Author(s):  
Hong Yan ◽  
Ming Fu Fu ◽  
Fa Yun Zhang ◽  
Guo Xiang Chen

The microstructural structures of SiCp/AZ61magnesium matrix composite were studied in three different casting processes, and their hardness was measured. The results indicated that SiCp/AZ61 composites fabricated in stirring melt casting process, compared to those in fully liquid stirring casting process and in semi-solid stirring casting process, possessed fairly uniform distribution of SiC particulates and few porosity rate. It was an ideal metal matrix composites fabricated process. The Vickers hardness of non-reinforcement AZ61 magnesium alloy is higher than that of semi-solid billet, and the Vickers hardness of SiCp/AZ61 composite is obviously higher than that of the matrix. In the meantime, the Vickers hardness of SiCp/AZ61 composite can be continuously enhanced with an increasing of volume fraction of SiC particles.


2019 ◽  
Vol 69 (12) ◽  
pp. 3503-3507
Author(s):  
Mariana Ciurdas ◽  
Daniela Alina Necsulescu ◽  
Cristian Mircea Pantilimon ◽  
Vasile Ion ◽  
Magdalena Galatanu ◽  
...  

Two mixtures of elemental nickel and titanium powders in atomic proportions of 50% Ni + 50% Ti and 32% Ni + 68% Ti, respectively, were ground for 40 hours in a high energy planetary mill. In the case of the first mixture, the mechanical alloying was totally produced, while for the second, the alloying was partial. In both mixtures, qualitative X-ray diffraction phase analysis revealed the presence of metastable phases, such as Ni HC and NiTi- R-phase. Also, the equiatomic mixture is characterized by a partially amorphous structure. 10% of each type of mixture submitted to milling was used as reinforcing element in the form of particulates for two magnesium matrix composites. They were obtained by sintering in the plasma at 590�C. In the case of the reinforced with the second mixture composite, the production of new phases other than the matrix and those present in the mixture of nickel and titanium powders after milling were recorded. The electron microscopy images of the two composites have resistant, free of micropores or microcracks matrix / particulates interfaces. The Mg-10% (32 at% Ni + 68 at% Ti) composite is characterized by Vickers hardness higher than that of the composite reinforced with the equiatomic mixture.


2015 ◽  
Vol 813-814 ◽  
pp. 257-262
Author(s):  
Govind Yadav ◽  
R.S. Rana ◽  
R.K. Dwivedi ◽  
Ankur Tiwari

Composite materials are important engineering materials due to their outstanding mechanical properties. Composites are materials in which the desirable properties of separate materials are combined by mechanically binding them together. Each of the components retains its structure and characteristic, but the composite generally possesses better properties. Composite materials offer superior properties to conventional alloys for various applications as they have high stiffness, strength and wear resistance. The development of these materials started with the production of continuous-fiber-reinforced composites. The high cost and difficulty of processing these composites restricted their application and led to the development of discontinuously reinforced composites. The aim involved in designing metal matrix composite materials is to combine the desirable attributes of metals and ceramics. The addition of high strength, high modulus refractory particles to a ductile metal matrix produce a material whose mechanical properties are intermediate between the matrix alloy and the ceramic reinforcement. Metal Matrix Composites with Aluminum as metal matrix is the burning area for research now a days.


2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Shashi Prakash Dwivedi ◽  
Satpal Sharma ◽  
Raghvendra Kumar Mishra

AbstractThe mechanical behavior, physical behavior, microstructural characteristics, and corrosion behavior of AA2014/silicon carbide (SiC)/carbonized eggshell hybrid green metal matrix composites (MMCs) were investigated. Twenty-five samples of hybrid composite with different combinations of SiC and carbonized eggshell particles in AA2014 matrix alloy were prepared. Microstructure presents that the reinforcement particles (SiC and eggshells) are uniformly distributed in the matrix AA2014 alloy. Transmission electron microscope image shows proper wettability between SiC, carbonized eggshell, and AA2014 aluminum alloy. The tensile strength and the fatigue strength for the composites containing 2.5 wt.% SiC up to 7.5 wt.% carbonized eggshell were observed to be higher than that of the other selected composites. The hardness values for the composites containing 12.5 wt.% SiC and 2.5 wt.% carbonized eggshell were in all cases higher than that of the other composites. The results show that toughness decreases with the increase in the weight ratio of SiC and carbonized eggshell in the composites. The results reveal that the sample of AA2014/2.5% SiC/12.5% carbonized eggshell shows minimum corrosion rate among all the selected samples. Density, porosity, and overall cost of hybrid metal matrix composites were also calculated to see the effects of carbonized eggshell and SiC addition in AA2014 matrix alloy.


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