Mechanistic studies in combustion synthesis of NiAl–TiB2 composites: Effects of gravity

2001 ◽  
Vol 16 (6) ◽  
pp. 1614-1625 ◽  
Author(s):  
Cheryl Lau ◽  
Alexander Mukasyan ◽  
Aleksey Pelekh ◽  
Arvind Varma
Keyword(s):  
Particle Size ◽  
Combustion Synthesis ◽  
Combustion Front ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Liquid Solution ◽  
Matrix Composites ◽  
Mechanistic Studies ◽  
Entire Surface ◽  
Microgravity Conditions

Combustion synthesis (CS) of NiAl-based materials reinforced by TiB2 particles was investigated under both terrestrial and microgravity conditions. The synthesized metal matrix composites (MMC) are characterized by very fine (<1 μm) reinforced particulates, which have strong bonding along their entire surface with matrix (NiAl) and are distributed uniformly in it. It was found that microgravity leads to a decrease in the average TiB2 particle size, while higher volume fraction of NiAl component in the material leads to the formation of coarser reinforced particulates. The mechanism of structure formation of different MMCs during CS was identified by using the quenching technique. For example, it was shown that TiB2 grains appear due to crystallization from the complex (Ni–Al–Ti–B) liquid solution formed in the combustion front. An overall decrease of microstructural transformation rates was observed under microgravity.

scholarly journals A New Model for Predicting Low Cycle Fatigue Behavior of Discontinuously Reinforced Metal Matrix Composites

2021 ◽  
Author(s):  
Qian Zhang
Keyword(s):  
Particle Size ◽  
Crack Initiation ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Plastic Strain Amplitude ◽  
Strain Hardening Exponent ◽  
Matrix Composites

An analytical model for predicitng the crack inititation life of low cycle fatique (LCF) of discontinuously reinforced metal matrix composites (DR-MMCs) has been proposed. The effects of the volume fraction Vf cyclic strain hardening exponent n' and cyclic strength coefficient K' on the LCF crack initiation life of DR-MMCs were analyzed. While both the lower level of the plastic strain amplitude and the lower Vf were found to increase the LCF crack initiation resistance, the effects of n' and K' were more complicated. By considering the enhanced dislocation density in the matrix and the load bearing effect of particles, a quantitative relationship between the LCF life of DR-MMCs and particle size was also derived. This model showed that a decreasing particle size results in a longer LCF life. The theoretical predictions based on the proposed models were found to be in good agreement with the experimental data reported in the literature.

Effects of Particle Size and Volume Fraction on Extrusion Texture of SiCp/Al Metal Matrix Composites

2011 ◽  
Vol 194-196 ◽  
pp. 1437-1441 ◽  
Author(s):  
Chun Lin He ◽  
Jian Ming Wang ◽  
Qing Kui Cai
Keyword(s):  
Particle Size ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Deformation Texture ◽  
Fiber Texture ◽  
Matrix Composites ◽  
Texture Intensity ◽  
Sic Particles ◽  
Al Matrix

The texture development was investigated in the extruded Al and Al metal matrix composites (MMCs) reinforced with SiC particles of different sizes and volume fractions. During extrusion, both the unreinforced Al and the MMCs develop a strong fiber texture with two components: <111> and <100>. When SiC is introduced into aluminum, the main component of texture is not modified, but the intensity of the component evolves with the volume fraction and average size of SiC particles. For the MMCs reinforced with 3.5μm SiC particles, the texture intensity of the Al matrix tends to decrease as the SiC volume fraction increases, and it is lower than that in the unreinforced Al. However, for the MMCs reinforced with 25 nm and 150 nm SiC particles, the texture intensity of the Al matrix is higher than that in the unreinforced matrix, and it increases with increasing the SiC volume fraction. It is found that superfine particles may introduce some new component into the deformation texture, and the texture intensity increases as the SiC particle size decreases.

A Physics-Based Model for Metal Matrix Composites Deformation During Machining: A Modified Constitutive Equation

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
M. N. A. Nasr ◽  
A. Ghandehariun ◽  
H. A. Kishawy
Keyword(s):  
Particle Size ◽  
Constitutive Equation ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Analytical Models ◽  
Force Model ◽  
Matrix Composites ◽  
New Approach ◽  
Particle Cracking

One of the main challenges encountered in modeling the behavior of metal matrix composites (MMCs) during machining is the availability of a suitable constitutive equation. Currently, the Johnson–Cook (J–C) constitutive equation is being used, even though it was developed for homogeneous materials. In such a case, an equivalent set of homogeneous parameters is used, which is only suitable for a particular combination of particle size and volume fraction. The current work presents a modified form of the J–C constitutive equation that suits MMCs, and explicitly accounts for the effects of particle size and volume fraction, as controlled parameters. Also, an energy-based force model is presented, which considers particle cracking and debonding based on the principles of fracture mechanics. In order to validate the new approach, cutting forces were predicted and compared to experimental results, where a good agreement was found. In addition, the predicted forces were compared to other analytical models available in the literature.

Combustion Synthesis of TiB2 Particle Dispersed Metal Matrix Composites

2007 ◽  
Vol 539-543 ◽  
pp. 809-813 ◽  
Author(s):  
Kiyotaka Matsuura ◽  
Yuki Obara
Keyword(s):  
Combustion Synthesis ◽  
Metal Matrix Composites ◽  
Powder Mixture ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Ceramic Particle ◽  
Tib2 Particle ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Tib2 Particles

FeAl-TiB2 composites have been combustion synthesized from mixtures of Fe, Al, Ti and B powders. When the powder mixture was heated in vacuum to approximately 900 K, an abrupt increase in temperature was observed, indicating that the combustion synthesis reactions occurred in the powder mixture. X-ray diffraction analyses revealed that the combustion-synthesized sample consisted of only FeAl and TiB2. Metallographic investigations using a scanning electron microscope revealed that fine TiB2 particles were dispersed in FeAl matrix phase. As the volume fraction of the TiB2 particles increased from 0.3 to 0.8 by controlling the powder mixture composition, the average TiB2 particle size increased to 1 to 7 μm and the average Vickers hardness of the composites increased from 800 to 1600. This method has been applied to the fabrication of some other ceramic particle dispersed metal matrix composites such as Fe-TiC and FeAl-TiC systems.

scholarly journals A New Model for Predicting Low Cycle Fatigue Behavior of Discontinuously Reinforced Metal Matrix Composites

2021 ◽  
Author(s):  
Qian Zhang
Keyword(s):  
Particle Size ◽  
Crack Initiation ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Plastic Strain Amplitude ◽  
Strain Hardening Exponent ◽  
Matrix Composites

An analytical model for predicitng the crack inititation life of low cycle fatique (LCF) of discontinuously reinforced metal matrix composites (DR-MMCs) has been proposed. The effects of the volume fraction Vf cyclic strain hardening exponent n' and cyclic strength coefficient K' on the LCF crack initiation life of DR-MMCs were analyzed. While both the lower level of the plastic strain amplitude and the lower Vf were found to increase the LCF crack initiation resistance, the effects of n' and K' were more complicated. By considering the enhanced dislocation density in the matrix and the load bearing effect of particles, a quantitative relationship between the LCF life of DR-MMCs and particle size was also derived. This model showed that a decreasing particle size results in a longer LCF life. The theoretical predictions based on the proposed models were found to be in good agreement with the experimental data reported in the literature.

Effect of particle size and volume fraction on the strengthening mechanisms of boron carbide reinforced aluminum metal matrix composites

2018 ◽  
Vol 233 (4) ◽  
pp. 1345-1356 ◽  
Author(s):  
Ritesh Raj ◽  
DG Thakur
Keyword(s):  
Particle Size ◽  
Yield Strength ◽  
Metal Matrix Composites ◽  
Strain Gradient ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Optical Microscope ◽  
Analytical Models ◽  
Matrix Composites ◽  
Strengthening Mechanisms

In the present work, 6061 Al–B4C metal matrix composites with different volume fractions (5, 10, 15 and 20 vol.%) have been fabricated by a low cost modified stir casting technique. The effect of varying particulate content on the microstructure of Al–B4C composites has been qualitatively characterized using a scanning electron microscope and an optical microscope. Tensile tests were performed to study the influence of varying reinforcement content on the strengthening behavior of fabricated composites. The composite’s yield strength increases significantly as the B4C content was increased from 0 to 20 vol.%. The enhancement in strength was elucidated on the basis of strengthening mechanisms characterized by load transfer, thermal dislocation, grain size, and strain gradient strengthening. The strengthening mechanisms were quantitatively analyzed and evaluated as a function of particle size and volume fraction. A critical particle size was found to be about 45 µm, below which the strengthening contributions from different mechanism increases remarkably. At a higher volume fraction of B4C, the effect of thermal dislocation strengthening becomes more dominant as compared to other mechanisms. Furthermore, the analytical models proposed by Ramakrishnan and Chen for predicting the yield strength of particulate reinforced metal matrix composites have been extended to take into account the contribution of strain gradient effect in the strengthening mechanism of composites.

Finite Element Analysis about Effects of Particle Size on Deformation Behavior of Particle Reinforced Metal Matrix Composites

2007 ◽  
Vol 353-358 ◽  
pp. 1263-1266
Author(s):  
Yi Wu Yan ◽  
Lin Geng ◽  
Ai Bin Li ◽  
Guo Hua Fan
Keyword(s):  
Particle Size ◽  
Finite Element ◽  
Metal Matrix Composites ◽  
Deformation Behavior ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Matrix Composites ◽  
Particle Volume ◽  
Element Analysis

By incorporating the Taylor-based nonlocal theory of plasticity, the finite element method (FEM) is applied to investigate the effect of particle size on the deformation behavior of the metal matrix composites. In the simulation, the two-dimensional plane strain and random distribution multi-particles model are used. It is shown that, at a fixed particle volume fraction, there is a close relationship between the particle size and the deformation behavior of the composites. The yield strength and plastic work hardening rate of the composites increase with decreasing particle size. The predicted stress-strain behaviors of the composites are qualitative agreement with the experimental results.

A model for volume fraction and/or particle size selection in metal matrix composites

2011 ◽  
Vol 530 ◽  
pp. 574-579 ◽  
Author(s):  
X.Z. Kai ◽  
Z.Q. Li ◽  
W.L. Zhang ◽  
G.L. Fan ◽  
L. Jiang ◽  
...  
Keyword(s):  
Particle Size ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Matrix Composites ◽  
Size Selection
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