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

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.

2021 ◽  
Author(s):  
F. A. Mirza ◽  
Daolun Chen

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.


Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 125
Author(s):  
Seyed Kiomars Moheimani ◽  
Mehran Dadkhah ◽  
Mohammad Hossein Mosallanejad ◽  
Abdollah Saboori

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.


2014 ◽  
Vol 1042 ◽  
pp. 58-64 ◽  
Author(s):  
Santanu Sardar ◽  
Santanu Kumar Karmakar ◽  
Debdulal Das

Metal matrix nanocomposites (MMNCs) have emerged as an important class of materials for structural applications specifically in the automobile and aerospace sectors; however, development of cost effective mass production technique of MMNCs with requisite operational and geometrical flexibilities is still a great challenge. Focused research in the last decade has highlighted that ultrasonic cavitation based processing is the most promising method for manufacturing of MMNCs with nearly uniform distribution of nanoparticles, having added advantage of being a liquid-phase route. This article presents an overview on the basic principles and recent advances in the ultrasonic cavitation based processing of MMNCs with a particular emphasis on identifying relationships amongst processing variables, microstructural parameters and mechanical properties. Critical issues of MMNCs fabrication are discussed.


Author(s):  
S. Jayalakshmi ◽  
R. Arvind Singh

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.


2013 ◽  
Vol 48 (12) ◽  
pp. 4191-4204 ◽  
Author(s):  
Chang-Soo Kim ◽  
Il Sohn ◽  
Marjan Nezafati ◽  
J. B. Ferguson ◽  
Benjamin F. Schultz ◽  
...  

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 537
Author(s):  
Chandrashekar A. ◽  
B. V. Chaluvaraju ◽  
Asif Afzal ◽  
Denis A. Vinnik ◽  
Abdul Razak Kaladgi ◽  
...  

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.


2021 ◽  
Vol 5 (2) ◽  
pp. 54
Author(s):  
Quinton Porter ◽  
Xiaochun Li ◽  
Chao Ma

The ability to produce metal matrix nanocomposites via pressing and infiltration was validated. Al/TiC nanocomposite was used as the model material. Pressing the powder in a die yielded cylindrical specimens with a green density of 1.98 ± 0.05 g/cm3, which was increased to only 2.11 ± 0.12 g/cm3 by sintering. Direct infiltration of the pressed specimens at 1050 °C for 3.5 h yielded specimens with a density of 3.07 ± 0.08 g/cm3, an open porosity of 3.06 ± 1.40%, and an areal void fraction of 8.09 ± 2.67%. The TiC nanoparticles were verified to be well dispersed using energy-dispersive X-ray spectroscopy. The measured hardness of 64 ± 3 HRA makes it a promising material for structural applications in industries such as aerospace and automotive.


2011 ◽  
Vol 239-242 ◽  
pp. 759-763
Author(s):  
Saheb Nouari

Agglomeration and poor distribution/dispersion of carbon nanotubes (CNTs) within the matrix remains a major problem in processing homogeneous CNT reinforced metal matrix nanocomposites. In this work, we examine the effect of processing on the dispersion of CNTs in Al6061 and Al2124 alloy based Nanocomposites. Three methods were used to prepare the nanocomposite powders. In the first, CNTs were mixed with the prealloyed powder through dry ball milling. In the second, CNTs were sonicated then the prealloyed powder was added followed by sonication of the mixture and wet milling. In the third, the CNTs were functionalized, sonicated, and then the prealloyed powder was added followed by sonication of the mixture and wet milling. The effect of functionaliztion, sonication and type of milling on the dispersion of CNTs was evaluated.


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