Microstructural Aspects of Some Magnesium Matrix Composites Reinforced with Amorphous/Nanocrystalline Ni-Ti Particulates

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.

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.


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.


JOM ◽  
2016 ◽  
Vol 68 (3) ◽  
pp. 908-919 ◽  
Author(s):  
E. S. Dvilis ◽  
O. L. Khasanov ◽  
V. N. Gulbin ◽  
M. S. Petyukevich ◽  
A. O. Khasanov ◽  
...  

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.


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.


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.


2018 ◽  
Vol 1 (1) ◽  
pp. 36
Author(s):  
Hualun Ding ◽  
Ximin Gong ◽  
Iaoxuan Shang

<p>This paper chooses magnesium as the matrix of composite materials, selects carbon fiber as reinforcement, and designs the composite scheme according to the structure and performance of Mg-based composites. The performance characteristics and application prospect of fiber-reinforced magnesium matrix composites are introduced. Wait. In this paper, the process of preparing carbon fiber magnesium matrix composites by compression casting method and spray deposition method is designed. The process flow chart of these two design schemes is determined by analyzing the principle of these two kinds of preparation methods, and the specific problems of the process are analyzed and summarized. </p>


2010 ◽  
Vol 89-91 ◽  
pp. 692-696 ◽  
Author(s):  
Ji Ming Zhou ◽  
Le Hua Qi ◽  
Hai Bo Ouyang ◽  
He Jun Li

Magnesium matrix composites are attractive for weight critical application, such as automotive and aerospace components, because of its high specific strength and stiffness. Extrusion process directly following vacuum infiltration (EVI) can eliminate the porosity and obtain the well-aligned and uniform fiber distribution during the fabrication of Csf/AZ91D composite. This process combines the advantages of gas pressure infiltration, squeeze casting, and semi-solid extrusion. The mechanical properties of the magnesium are improved greatly by introducing the carbon fibers into the magnesium matrix through the EVI process. In the present study, the carbon short fiber reinforced magnesium matrix composites Csf/AZ91D were fabricated by EVI process. The microstructure and tensile property of Csf/AZ91D composites were investigated. The results showed that the microstructure of the composite presented a uniform distribution of carbon short fibers in the matrix and good interfacial integrity. The yield strength and stiffness of the composites increased with increasing carbon short fiber content, but at the cost of ductility. Nonetheless, Csf/AZ91D can keep relatively high ductility during the improvement of strength compared with reported composites in the literatures. Increasing carbon fiber content in the composite was not always beneficial to the ultimate tensile strength at the same magnitude. When the fiber content exceeds 10%, the matrix was not strengthened as greatly as under 10% fiber content. The yield strength improvement was attributed to (i) load-bearing effects due to the presence of carbon short fiber reinforcements; (ii) grain size refinement due to the large extrusion deformation; (iii) generation of dislocations to accommodate CTE mismatch between the matrix and the particles.


2018 ◽  
Vol 207 ◽  
pp. 03019
Author(s):  
Yun-si Wang ◽  
Rui-long Niu ◽  
Fang-jia Yan ◽  
Dong-ping Duan ◽  
Xue-min Yang

Due to inherent high damping capacities of Mg, Mg-based alloys or composites can absorb enormous elastic energy, thus, can be used as damping materials playing important role in reducing vibration and noise. Spherical Mg2Si magnesium matrix composites were prepared by super-gravity method with fly ash floating beads with particle sizes of 80, 125 and 500 μm. The microstructures and damping capacities of prepared samples were discussed. Spherical and fragment-shaped Mg2Si phases were observed in the matrix by SEM micrograph. Increasing particle size of fly ash floating beads can lead to an obviously decreasing tendency of internal friction tan φ. The critical strain εcr=1.9×10−2 of ε – tan φ curve and critical temperature Tcr=150 °C of T – tan φ curve for tan φ changing from slowly to greatly increasing. Damping peaks occur in the vicinity of strain ε=5.2×10−2 in ε –tan φ curve whereas no damping peaks occur in T –tan φ curve.


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