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.

Recent advances in research on magnesium alloys and magnesium–calcium phosphate composites as biodegradable implant materials

2016 ◽  
Vol 31 (6) ◽  
pp. 878-900 ◽  
Author(s):  
Katarzyna Kuśnierczyk ◽  
Michał Basista
Keyword(s):  
Mechanical Properties ◽  
Metal Matrix Composites ◽  
Magnesium Alloys ◽  
Metal Matrix ◽  
Calcium Phosphates ◽  
Second Phase ◽  
Matrix Composites ◽  
Alloy Matrix ◽  
Biodegradable Implant

Magnesium alloys are modern biocompatible materials suitable for orthopaedic implants due to their biodegradability in biological environment. Many studies indicate that there is a high demand to design magnesium alloys with controllable in vivo corrosion rates and required mechanical properties. A solution to this challenge can be sought in the development of metal matrix composites based on magnesium alloys with addition of relevant alloying elements and bioceramic particles. In this study, the corrosion mechanisms along with corrosion protection methods in magnesium alloys are discussed. The recently developed magnesium alloys for biomedical applications are reviewed. Special attention is given to the newest research results in metal matrix composites composed of magnesium alloy matrix and calcium phosphates, especially hydroxyapatite or tricalcium phosphate, as the second phase with emphasis on the biodegradation behavior, microstructure and mechanical properties in view of potential application of these materials in bone implants.

scholarly journals A brief review on mechanical properties of Al-MMCs fabricated by stir casting route & applications

2021 ◽  
Vol 309 ◽  
pp. 01227
Author(s):  
Abhishek Thakur ◽  
Ravinder Singh Joshi ◽  
Arshpreet Singh
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Fly Ash ◽  
Chemical Composition ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Stir Casting ◽  
Second Phase ◽  
Matrix Composites ◽  
Aluminium Metal

Aluminium metal matrix composites are pretty much important in the different demanding sectors such as in the field of medicine and engineering like automobiles, aerospace, defence, dental and consumer goods. The need arises due to its huge calibre in industrial need of good materials with lighter weight, excellent properties and economical in cost demanded the researchers or scientists research on composite materials. The AMMCs or Al-MMCs consists of an apex variety of mechanical properties which is directly proportional to the chemical composition of the Aluminium matrix. To enhance strength the reinforcement plays a key role in AMMCs could be in the form of continuous/ discontinuous fibres, whiskers & particulate as the second phase depending on their applications and property requirements. In addition to it, various strength enhancers are reinforcements such as fly ash, TiC, SiC, Al2O3, TiO2, B4C etc. This paper attempts to review the different combinations in the processing of aluminium metal matrix composites along with their properties and their applications.

Nano and macromechanical properties of aluminium (A356) based hybrid composites reinforced with multiwall carbon nanotubes/alumina fiber

2016 ◽  
Vol 51 (11) ◽  
pp. 1631-1642 ◽  
Author(s):  
JSS Babu ◽  
A Srinivasan ◽  
CG Kang
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Hybrid Composites ◽  
Multiwall Carbon Nanotubes ◽  
Matrix Composites ◽  
Weight Percentage ◽  
Continuous Stiffness Measurement ◽  
Multiwall Carbon

Nano-microhybrid reinforced metal matrix composites are the novel combination of composite system which enhanced the mechanical properties of the metal matrix composites. The aim of this study is to determine the nano- and macromechanical properties of aluminium (A356)-based hybrid composites reinforced with multiwall carbon nanotubes and alumina short fibers (Al2O3sf). Hybrid preforms were developed initially, by a combination of multiwall carbon nanotubes and Al2O3sf with total volume fractions of 10%, 15% and 20% and by varying the weight percentage of multiwall carbon nanotubes such as 1%, 2% and 3%. The fabricated hybrid preforms were then infiltrated with aluminium alloy (A356), and the microstructure and mechanical properties of the composites were evaluated. The distribution of multiwall carbon nanotubes within the array of the Al2O3sf network which exists in clusters was found to be relatively good. The mechanical properties such as the hardness and tensile strength of Al-based hybrid metal matrix composites were found to be improved by up to 2 wt% of multiwall carbon nanotubes. The causative reason for this is attributed to a combined effect of both multiwall carbon nanotubes and Al2O3sf, which contributed to better load sharing between the fibers and the Al matrix, and also accounted for the resistance of dislocation movements caused by the presence of the multiwall carbon nanotubes. In addition, the continuous stiffness measurement method was also used to evaluate the nanomechanical properties of the composites. The results showed that the influence of multiwall carbon nanotubes highlighted the properties on a nanoscale.

scholarly journals Effect of the Nanotube Radius and the Volume Fraction on the Mechanical Properties of Carbon Nanotube-Reinforced Aluminum Metal Matrix Composites

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3947
Author(s):  
Myung Eun Suk
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Fracture Strain ◽  
Volume Fraction ◽  
Strain Curve ◽  
Matrix Composites ◽  
Strength And Stiffness ◽  
Walled Carbon Nanotubes

By using the advantages of carbon nanotubes (CNTs), such as their excellent mechanical properties and low density, CNT-reinforced metal matrix composites (MMCs) are expected to overcome the limitations of conventional metal materials, i.e., their high density and low ductility. To understand the behavior of composite materials, it is necessary to observe the behavior at the molecular level and to understand the effect of various factors, such as the radius and content of CNTs. Therefore, in this study, the effect of the CNT radius and content on the mechanical properties of CNT-Al composites was observed using a series of molecular dynamics simulations, particularly focusing on MMCs with a high CNT content and large CNT diameter. The mechanical properties, such as the strength and stiffness, were increased with an increasing CNT radius. As the CNT content increased, the strength and stiffness increased; however, the fracture strain was not affected. The behavior of double-walled carbon nanotubes (DWNTs) and single-walled carbon nanotubes (SWNTs) was compared through the decomposition of the stress–strain curve and observations of the atomic stress field. The fracture strain increased significantly for SWNT-Al as the tensile force was applied in the axial direction of the armchair CNTs. In the case of DWNTs, an early failure was initiated at the inner CNTs. In addition, the change in the elastic modulus according to the CNT content was predicted using the modified rule of mixture. This study is expected to be useful for the design and development of high-performance MMCs reinforced by CNTs.

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.

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