scholarly journals Investigation on the Strengthening Mechanisms of Nickel Matrix Nanocomposites

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1426
Author(s):  
Íris Carneiro ◽  
José Valdemar Fernandes ◽  
Sónia Simões
Keyword(s):  
Grain Refinement ◽  
Metal Matrix ◽  
Load Transfer ◽  
Second Phase ◽  
Strengthening Effect ◽  
Small Contribution ◽  
Strengthening Mechanisms ◽  
Metal Matrix Nanocomposites ◽  
The Matrix ◽  
Matrix Nanocomposites

The strengthening effect of carbon nanotubes (CNTs) in metal matrix nanocomposites occurs due to several mechanisms that act simultaneously. The possible strengthening mechanisms for metal matrix nanocomposites reinforced with CNTs consist of: (1) load transfer, (2) grain refinement and texture strengthening, (3) second phase strengthening, and (4) strain hardening. The main focus of this work is to identify the strengthening mechanisms that play a role in the case of the Ni-CNT nanocomposite produced by powder metallurgy. For the dispersion and mixing of the metallic powders with CNTs, two different routes were performed by ultrasonication and ball milling. The results indicated that four different strengthening mechanisms are present in the nanocomposites and had a different contribution to the final mechanical properties. The load transfer and the increase in dislocation density seem to strongly affect the properties and microstructure of the nanocomposite. The grain refinement and the presence of second phase particles have a small contribution in the strengthening of this nanocomposite, since the introduction of CNTs in the Ni matrix slightly affects the size and orientation of the grains in the matrix and a few nanometric particles of Ni3C were identified.

scholarly journals Strengthening Mechanisms in Carbon Nanotubes Reinforced Metal Matrix Composites: A Review

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1613
Author(s):  
Íris Carneiro ◽  
Sónia Simões
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Load Transfer ◽  
Second Phase ◽  
Matrix Composites ◽  
Strengthening Mechanisms ◽  
Metal Matrix Nanocomposites ◽  
Main Challenge

Carbon nanotubes (CNTs)-reinforced metal matrix composites are very attractive advanced nanocomposites due to their potential unusual combination of excellent properties. These nanocomposites can be produced by several techniques, the most reported being powder metallurgy, electrochemical routes, and stir or ultrasonic casting. However, the final mechanical properties are often lower than expected. This can be attributed to a lack of understanding concerning the strengthening mechanisms that act to improve the mechanical properties of the metal matrix via the presence of the CNTs. The dispersion of the CNTs is the main challenge in the production of the nanocomposites, and is independent of the production technique used. This review describes the strengthening mechanism that act in CNT-reinforced metal matrix nanocomposites, such as the load transfer, grain refinement or texture strengthening, second phase, and strain hardening. However, other mechanisms can occur, such as solid solution strengthening, and these depend on the metal matrix used to produce the nanocomposites. Different metallic matrices and different production techniques are described to evaluate their influence on the reinforcement of these nanocomposites.

scholarly journals Fabrication and Characterization of the Modified EV31-Based Metal Matrix Nanocomposites

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 125
Author(s):  
Seyed Kiomars Moheimani ◽  
Mehran Dadkhah ◽  
Mohammad Hossein Mosallanejad ◽  
Abdollah Saboori
Keyword(s):  
Thermal Expansion ◽  
Mechanical Strength ◽  
Metal Matrix ◽  
Coefficient Of Thermal Expansion ◽  
Structural Effect ◽  
Metal Matrix Nanocomposites ◽  
Mechanical Stirring ◽  
Specific Strength ◽  
The Matrix ◽  
Matrix Nanocomposites

Metal matrix nanocomposites (MMNCs) with high specific strength have been of interest for numerous researchers. In the current study, Mg matrix nanocomposites reinforced with AlN nanoparticles were produced using the mechanical stirring-assisted casting method. Microstructure, hardness, physical, thermal and electrical properties of the produced composites were characterized in this work. According to the microstructural evaluations, the ceramic nanoparticles were uniformly dispersed within the matrix by applying a mechanical stirring. At higher AlN contents, however, some agglomerates were observed as a consequence of a particle-pushing mechanism during the solidification. Microhardness results showed a slight improvement in the mechanical strength of the nanocomposites following the addition of AlN nanoparticles. Interestingly, nanocomposite samples were featured with higher electrical and thermal conductivities, which can be attributed to the structural effect of nanoparticles within the matrix. Moreover, thermal expansion analysis of the nanocomposites indicated that the presence of nanoparticles lowered the Coefficient of Thermal Expansion (CTE) in the case of nanocomposites. All in all, this combination of properties, including high mechanical strength, thermal and electrical conductivity, together with low CTE, make these new nanocomposites very promising materials for electro packaging applications.

Processing Routes, Mechanical, and Tribological Properties of Light Metal Matrix Nanocomposites

2017 ◽  
pp. 991-1037
Author(s):  
S. Jayalakshmi ◽  
R. Arvind Singh
Keyword(s):  
Tribological Properties ◽  
Metal Matrix ◽  
Base Material ◽  
Light Metal ◽  
Advanced Materials ◽  
Matrix Composites ◽  
Metal Matrix Nanocomposites ◽  
Mechanical And Tribological Properties ◽  
The Matrix ◽  
Matrix Nanocomposites

The chapter highlights the various processing/synthesizing routes of Light Metal Matrix Nanocomposites (LMMNCs), their microstructural characteristics, mechanical behaviour, and tribological properties. LMMNCs are advanced materials, in which nano-sized ceramic particles are reinforced into Al/Mg matrices. In conventional Metal Matrix Composites (MMCs), the incorporation of micron sized reinforcements in the matrix usually results in a considerable improvement in hardness and ultimate strength when compared to the unreinforced base material. However, most of these composites do not show plastic deformation (little or no yield) and exhibit drastic reduction in ductility. This poses a major limitation for MMCs to be used in real-time applications. In order to overcome this drawback, Al/Mg composites with nano-scale reinforcements have been developed. Based on numerous research works, it has been established that LMMNCs are better materials that possess superior properties, wherein both strength and ductility improvements along with excellent wear resistance can be achieved.

scholarly journals Mechanical and Corrosion Studies of Friction Stir Welded Nano Al2O3 Reinforced Al-Mg Matrix Composites: RSM-ANN Modelling Approach

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 537
Author(s):  
Chandrashekar A. ◽  
B. V. Chaluvaraju ◽  
Asif Afzal ◽  
Denis A. Vinnik ◽  
Abdul Razak Kaladgi ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Metal Matrix ◽  
Corrosion Properties ◽  
Metal Matrix Nanocomposites ◽  
X Ray ◽  
Friction Stir ◽  
The Matrix ◽  
Mechanical And Corrosion Properties ◽  
Al2o3 Particles ◽  
Matrix Nanocomposites

Nano aluminum oxide was prepared by the combustion method using aluminum nitrate as the oxidizer and urea as a fuel. Characterization of synthesized materials was performed using SEM (scanning electron microscope), powder XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), and TEM (transmission electron microscope). Al-Mg/Al2O3 (2, 4, 6, and 8 wt%) metal matrix nanocomposites were prepared by liquid metallurgy route-vertex technique. The homogeneous dispersion of nano Al2O3 particles in Al-Mg/Al2O3 metal matrix nanocomposites (MMNCs) was revealed from the field emission SEM analysis. The reinforcement particles present in the matrix were analyzed through energy-dispersive X-ray spectroscopy method. The properties (corrosion and mechanical) of the fabricated composites were evaluated. The mechanical and corrosion properties of the prepared nanocomposites initially increased and then decreased with the addition of nano Al2O3 particles in Al-Mg Matrix. The studies show that, the presence of 6 wt% of nano Al2O3 particles in the matrix improved the properties of other combinations of nano Al2O3 in the Al-Mg matrix material. Further, the Al-Mg/Al2O3 (6 wt%) MMNCs are joined by friction stir welding and evaluated for microstructural, mechanical, and corrosion properties. Al-Mg/Al2O3 MMNCs may find applications in the marine field. The response surface method (RSM) was used for the optimization of tensile strength, Young’s modulus, and microhardness of the synthesized material which resulted in a 95% of statistical confidence level. Artificial neural network (ANN) analysis was also carried out which perfectly predicted these two properties. The ANN model is optimized to obtain 99.9% accurate predictions by changing the number of neurons in the hidden layer.

scholarly journals Strengthening Mechanisms of Aluminum Matrix Nanocomposites Reinforced with CNTs Produced by Powder Metallurgy

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1711
Author(s):  
Íris Carneiro ◽  
José Valdemar Fernandes ◽  
Sónia Simões
Keyword(s):  
Powder Metallurgy ◽  
Aluminum Matrix ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Small Contribution ◽  
Strengthening Mechanisms ◽  
Electron Backscattered Diffraction ◽  
Phase Hardening ◽  
Uniform Dispersion ◽  
Matrix Nanocomposites

The present work aims to investigate the strengthening mechanisms in aluminum matrix nanocomposites reinforced by carbon nanotubes (CNTs). A classical powder metallurgy route produced Al-CNT nanocomposites using ultrasonication and ball milling as dispersion/mixture techniques. The microstructural characterization is crucial for this study to reach the objective, being performed mainly by electron backscattered diffraction (EBSD), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM). Uniform dispersion without damaging the CNTs structure is the key for the nanocomposite by powder metallurgy production process. The reinforcement effect occurs due to several strengthening mechanisms that act simultaneously. For the Al-CNT nanocomposites produced by ultrasonication as a dispersion/mixture technique, the observed improvement in the mechanical properties of nanocomposites can be attributed to the load transfer from the matrix to the CNTs. The strain hardening and the second-phase hardening can also have a small contribution to the strengthening of the nanocomposites.

scholarly journals A Unified Model for the Prediction of Yield Strength in Particulate-Reinforced Metal Matrix Nanocomposites

2021 ◽  
Author(s):  
F. A. Mirza ◽  
Daolun Chen
Keyword(s):  
Experimental Data ◽  
Yield Strength ◽  
Metal Matrix ◽  
Fuel Efficiency ◽  
Unified Model ◽  
Transportation Industry ◽  
Metal Matrix Nanocomposites ◽  
Structural Applications ◽  
The Matrix ◽  
Matrix Nanocomposites

Lightweighting in the transportation industry is today recognized as one of the most important strategies to improve fuel efficiency and reduce anthropogenic climate-changing, environment-damaging, and human death-causing emissions. However, the structural applications of lightweight alloys are often limited by some inherent deficiencies such as low stiffness, high wear rate and inferior strength. These properties could be effectively enhanced by the addition of stronger and stiffer reinforcements, especially nano-sized particles, into metal matrix to form composites. In most cases three common strengthening mechanisms (load-bearing effect, mismatch of coefficients of thermal expansion, and Orowan strengthening) have been considered to predict the yield strength of metal matrix nanocomposites (MMNCs). This study was aimed at developing a unified model by taking into account the matrix grain size and porosity (which is unavoidable in the materials processing such as casting and powder metallurgy) in the prediction of the yield strength of MMNCs. The Zener pinning effect of grain boundaries by the nano-sized particles has also been integrated. The model was validated using the experimental data of magnesium- and titanium-based nanocomposites containing different types of nano-sized particles (namely, Al2O3, Y2O3, and carbon nanotubes). The predicted results were observed to be in good agreement with the experimental data reported in the literature.

scholarly journals A Unified Model for the Prediction of Yield Strength in Particulate-Reinforced Metal Matrix Nanocomposites

2021 ◽  
Author(s):  
F. A. Mirza ◽  
Daolun Chen
Keyword(s):  
Experimental Data ◽  
Yield Strength ◽  
Metal Matrix ◽  
Fuel Efficiency ◽  
Unified Model ◽  
Transportation Industry ◽  
Metal Matrix Nanocomposites ◽  
Structural Applications ◽  
The Matrix ◽  
Matrix Nanocomposites

Lightweighting in the transportation industry is today recognized as one of the most important strategies to improve fuel efficiency and reduce anthropogenic climate-changing, environment-damaging, and human death-causing emissions. However, the structural applications of lightweight alloys are often limited by some inherent deficiencies such as low stiffness, high wear rate and inferior strength. These properties could be effectively enhanced by the addition of stronger and stiffer reinforcements, especially nano-sized particles, into metal matrix to form composites. In most cases three common strengthening mechanisms (load-bearing effect, mismatch of coefficients of thermal expansion, and Orowan strengthening) have been considered to predict the yield strength of metal matrix nanocomposites (MMNCs). This study was aimed at developing a unified model by taking into account the matrix grain size and porosity (which is unavoidable in the materials processing such as casting and powder metallurgy) in the prediction of the yield strength of MMNCs. The Zener pinning effect of grain boundaries by the nano-sized particles has also been integrated. The model was validated using the experimental data of magnesium- and titanium-based nanocomposites containing different types of nano-sized particles (namely, Al2O3, Y2O3, and carbon nanotubes). The predicted results were observed to be in good agreement with the experimental data reported in the literature.

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