Particles In Aluminum Matrix Research Articles

Fabrication of Aluminum 5083/SiC Surface Composite on Tungsten Inert Gas Weld Joint by Novel Direct Friction Stir Processing Technique

For the creation of surface reinforcement particles in the metal matrix, friction stir processing is frequently utilized. Formation of aluminum/SiC surface composite on Tungsten Inert Gas (TIG) butt weld of Al5083 by a novel technique of direct friction stir processing (DFSP) using a hollow tool is successfully demonstrated in this present work. Deposition of SiC in the stir zone of DFSP was confirmed by X-Ray diffraction (XRD) method. Micro analysis of weld joint was achieved using metallographic microscope and scanning electron microscope (SEM). Microstructure of stir zone of DFSP shows finely distributed SiC reinforcement particles in aluminum matrix. Absence of detrimental intermetallics was confirmed by energy dispersive spectroscopy (EDS) analysis. Tensile strength of DFSPed specimen was found to be 227.3 MPa which is 19.5% lower than UTS of autogenous TIG weld specimen. Microhardness of SZ of DFSP was found to be increased from TIG weld microhardness of 86 Hv to 107 Hv due to presence of SiC particles.

Melting temperature of Ti and TiAl nanoparticles in vacuum and in Al matrix depending on their diameter: molecular dynamics study

The dependence of the melting temperature of Ti and TiAl nanoparticles on their diameter in vacuum and in Al matrix was studied by the method of molecular dynamics using EAM potentials of Zope and Mishin. Particles with a diameter of 2.5 to 12 nm were considered. The obtained values of the melting point are in good agreement with the approximation curves constructed on the basis that the decrease in the melting temperature is proportional to the ratio of the surface area of the particle to its volume. Wherein the values of the melting temperature of Ti and TiAl particles in the aluminum matrix turned out to be lower than those of particles in vacuum, which is explained by the smearing and disordering of the interface due to mutual diffusion. As the size of particles in vacuum and in aluminum increased, the values of their melting points tended to the same value, which is explained by the decrease in the role of the diffusion-blurred interface with an increase in the particle diameter. The particles began to melt from the surface. The velocity of movement of the melting front depended on temperature and increased with increasing temperature. In the case of particles in aluminum matrix, at temperatures close to the particle melting point, mutual diffusion was significantly accelerated due to melting of the particle boundary layer. Al atoms penetrating into the particle accelerated the movement of the melting front, rapidly occupying the next destroyed layer of the particle.

Microstructural studies on aluminium metal matrix composite (Al7075-SiC) fabricated through stir casting process

In the present work Al7075 metal matrix reinforced with silicon carbide (SiC) powder is fabricated through stir casting route. Metal matrix composites were manufactured by altering percent weight fraction of silicon carbide powder as 5% & 7.5% by weight with average particle size of 50 µm. Microstructural evaluation and Vickers microhardness studies on stir casted Aluminium 7075 alloy which has silicon carbide (SiC) reinforcement are reported in current paper. After stir casting of composites, manufactured composite samples are examined by using optical microscope and scanning electron microscope (SEM) in order to study distribution SiC particles in aluminium matrix. The microstructural observations on metal matrix composites have reported the presence of SiC reinforcement in the matrix which are very much fairly distributed into the matrix phase. Also it can be seen that there is little clustering of SiC particles in Al7075 matrix and porosity in manufactured composites. It is also been found that microhardness of aluminium metal matrix composites was improved with increment in reinforcement content.

Study of friction force behaviour of red-mud based aluminium matrix composites under influence of various operating parameters

Fabrication of particulate composite with aluminum6061 reinforced with red-mud as reinforcement has been done by stir-casting. Uniform distribution of red-mud particles in aluminum matrix has been examined by Scanning electron microscopy. For confirmation of red-mud in the matrix, energy dispersive spectroscopy spectrum has been obtained from the surface. The results show that there has been first increase in friction force upto 12% red-mud and then decrease in friction force. Value of friction force has been found minimum at 125 µm particle size and maximum at 250 µm. Analysis reveals that friction force increases with increase in applied load and sliding distance. The effect of load and sliding speed on friction force has been reported significant by ANOVA analysis. Load has been found most effective parameter on friction force followed by sliding speed, sliding distance, particle size and aging time. Response table shows percentage reinforcement has least effect on friction force.

Effect of Zr content on the precipitation and dynamic softening behavior in Al–Fe–Zr alloys

In this paper, the precipitation and dynamic softening behavior of Al–Fe–Zr alloys were investigated by transmission electron microscopy (TEM), electron back scattering diffraction (EBSD), and the precipitation thermodynamics was studied by JmatPro software. Results show that the optimizing temperature of Al3Zr precipitates was 350 °C and the fraction of butterfly-shaped Al3Zr and rod-shaped Al3Fe reached a peak at ~350 °C. With the increase of Zr content, the fraction of Al3Zr increased, whereas its size and morphology had almost no change. The fraction and morphology of Al3Fe showed less variation with Zr content. Dynamic recovery and dynamic recrystallization occurred during extrusion. The two kinds of precipitation particles in aluminum matrix pinned the dislocations and inhibited dynamic recrystallization effectively. As the Zr content went up from 0.1 to 0.4 wt%, the inhibition got stronger and the fraction of recrystallized grains decreased from 44.2% to 86.9%. As a consequence of the dynamic recrystallization suppression, dynamic recovery became the major softening mechanism.

Mechanical and wear Characteristics of Aluminium Alloy 7075 Reinforced with Nano-Aluminium Oxide/ Magnesium Particles by Stir casting Method

In the present days, Industrial sectors are choosing aluminium-based metal matrix Nanocomposites (AMMNCs) for aerospace, structural, vehicle and marine applications for its much less cost, low weight, and high strength to weight proportion. The objective of producing metal matrix Nanocomposite is to incorporate the desirable qualities of metals and ceramic fragments to the base metal. In this study, we made a hybrid composite by strengthened Nano-aluminium oxide (Al 2 O 3 ) with Aluminium7075 alloy and Magnesium (1 % fixed) by the process of Liquid metallurgy path (stir casting). When compared to various other strategies, this method is least expensive and also most reliable. The hardness test and wear test was carried out on the composite samplings that are made by stir casting approach. The results reveal that the consolidation of Nano- aluminium oxide reinforcement particles in aluminium matrix increases the mechanical and wear properties.

Optimization on machining parameters of aluminium alloy hybrid composite using carbide insert

In this experimental work, three different aluminium alloy based composites were developed by using Al 6061, AA 2024 and AA 7075 as matrix materials and Graphene (2 wt%) as reinforcement material. The fabrication of nano composites were carried out using powder metallurgy route followed by hot extrusion. The extruded samples of the three composites were subjected to turning experiments to explore its machinability. Five parameters namely, type of work material, cutting tool material, cutting speed, feed rate and depth of cut are considered for the turning experiments. Taguchi L18 mixed orthogonal array with three levels of cutting speeds (35, 50 and 65 m min−1), feed rates (0.1, 0.2, 0.3 mm/rev), depth of cut (0.6, 0.8, 1 mm), three different work (composite) materials and two levels of cutting tool (Uncoated and DLC Coated carbide) materials was used for the design of experiment. Cutting force generated during the machining process, surface roughness and surface hardness obtained on the machined surface of the specimen and flank wear on the tool subsequent to machining are recorded for further analysis. Analysis of Variance (ANOVA) was carried out using the experimental data to determine the significance of each variable parameter on the response parameter. From ANOVA, it has been noted that AA6061 based composite has encountered significant cutting force when compared to other two composite. Likewise work material have more influence on surface roughness while comparing the other machining parameters and AA7075 based composite was found to result in better surface finish. Cutting speed has significantly influenced the flank wear followed by the tool material and it was found that uncoated carbide has undergone more wear than the DLC coated carbide insert. Further, it is evident from micro structural and FESEM analysis that there is a homogeneous distribution of Graphene particles in aluminium matrix after hot extrusion.

Preparation and evaluation of mechanical properties of 6061Al-Al2O3 metal matrix composites by stir casting process

Abstract Aluminium oxide particle (0–4 wt%) reinforced Al6061 alloy metal matrix composites have been prepared using stir casting process. Mechanical properties such as hardness, tensile strength and compression of composites have been tested and the values are compared with Al6061 alloy. The results reveal that mechanical properties of MMC is greatly enhanced by the addition of Al2O3 particles in Al6061 alloy. Hardness, ultimate tensile strength and compression strength of Al6061 alloy increased with increasing weight fraction of aluminium oxide particles in aluminium matrix. This developed MMC can be used in automotive applications because of its excellent mechanical properties while compared to Al6061 alloy.

Metal matrix nano composites using graphene nano platelets indented on copper particles in aluminium matrix

Metal matrix nano composites using graphene nano platelets indented on copper particles in aluminium matrix

Morphological and Wear behaviour of new Al-SiCmicro-SiCnano hybrid nanocomposites fabricated through powder metallurgy

In the present work, aluminium matrix composites reinforced with 10 wt% SiC micro particles along with x% SiC nano particles (x = 0, 1, 3, 5 and 7 wt%) were fabricated through powder metallurgy. The fabricated hybrid composites were characterized by x-ray diffractometer (XRD), scanning electron microscope (SEM), energy dispersive spectrum (EDS) and elemental mapping. The relative density, hardness and wear behaviour of all hybrid nanocomposites were studied. The influence of various control factors like SiC reinforcement, sliding distance (300, 600, 900 and 1200 m) and applied load (20, 30 and 40 N) were explored using pin-on-disc wear apparatus. The uniform distribution of micro and nano SiC particles in aluminium matrix is confirmed by elemental maps. The hardness and wear test results showed that properties of the hybrid composite containing 5 wt% nano SiC was better than other hybrid composites. Additionally, the wear loss of all hybrid nanocomposites increases with increasing sliding distance and applied load. The identification of wear phenomenon were studied through the SEM images of worn surface.

Studies on microstructure and mechanical behaviour of A7075- Flyash/SiC hybrid metal matrix composites

Experiments have been performed under laboratory condition to review the mechanical behaviour of the hybrid composites with aluminium matrix A7075 alloy, reinforced with silicon carbide (SiC) and Flyash. This has been possible by fabricating the samples through usual stir casting technique. Scanning electron microscopy was used for microstructure analysis. Chemical characterization of both matrix and composites was performed by using EDAX. Density, hardness, tensile and deformation studies were conceded out on both the base alloy and composites. Enhanced hardness and deformed properties were observed for all the composites. Interestingly improved tensile results were obtained for the composites than alloy. Dispersion of (SiC) and Flyash particles in aluminium matrix enhances the hardness of the composites.

Influence of surface morphology and UFG on damping and mechanical properties of composite reinforced with spinel MgAl2O4-SiC core-shell microcomposites

Interface between ceramic particulate and matrix is known to control the response of the materials and functionality of the composite. Among numerous physical properties, grain structure of the materials has also played a significant role in defining the behaviour of metal matrix composites. Usually, silicon carbide (SiC) particles show poor interfacial wettability in aluminium melt. Herein, we were successfully synthesized magnesium oxide (MgO) and nanocrystalline magnesium aluminate (MgAl2O4) spinel coated silicon carbide (SiC) core-shell micro-composites through sol-gel technique to improve the wettability of dispersoids. Core-shell structures of submicron size were thoroughly investigated by various characterization techniques. Further, aluminium matrix composites incorporated with pristine SiC, MgO grafted SiC and MgAl2O4 grafted SiC particles were fabricated by stir casting technique, respectively. Additionally, as-cast composites were processed via friction stir processing (FSP) technique to observe the influence of grain refinement on mechanical and damping properties. Electron back scattered diffraction (EBSD), Field emission scanning electron microscopy (FE-SEM) and X-ray energy dispersion spectroscopy (EDX) analysis were conducted for investigating grain size refinement, adequate dispersion, stability and de-agglomeration of encapsulated SiC particles in aluminium matrix. The mechanical as well as thermal cyclic (from −100 to 400°C) damping performance of the as-cast and friction stir processed composites were studied, respectively. Finally, the enhanced properties were attributable to reduced agglomeration, stabilization and proper dispersion of the tailored SiC particles Al matrix.

Experimental investigations on mechanical behavior of aluminium metal matrix composites

Today we are widely using aluminium based metal matrix composite for structural, aerospace, marine and automobile applications for its light weight, high strength and low production cost. The purpose of designing metal matrix composite is to add the desirable attributes of metals and ceramics to the base metal. In this study we developed aluminium metal matrix hybrid composite by reinforced Aluminium7075 alloy with silicon carbide (SiC) and aluminium oxide (alumina) by method of stir casting. This technique is less expensive and very effective. The Hardness test and Wear test were performed on the specimens which are prepared by stir casting techniques. The result reveals that the addition of silicon carbide and alumina particles in aluminium matrix improves the mechanical properties.

Mechanical properties and microstructure characterization of spark plasma and conventional sintering of Al–SiC–TiC composites

This work presents fabrication and characterization of Al–SiC–TiC composite materials containing 15 wt% SiC and 5 wt% TiC as reinforcing phases. The spark plasma and conventional sintering were done at 440 °C for 25 min and 600 °C for 60 min, respectively. The results indicate that the mechanical properties obtained by sprak plasma process are much higher than conventional sintering. The 99.2 ± 0.4% and 90.4 ± 0.7% of theoretical density were measured for samples sintered by SPS and conventionally, respectively. XRD analyses indicate no decomposition of SiC and TiC reinforcements. SEM investigations demonstrate uniform distribution of reinforcement particles in aluminum matrix and also fine microstructure of the SPS samples.

Nanostructured powder for nano-B4C particulate-reinforced aluminium–matrix composite prepared via cryomilling

Nanostructured powders for aluminium-based composite reinforced with nanometric B4C particles were synthesised by cryomilling. The morphology evolution of Al/B4C powder during cryomilling was observed by scanning electron microscopy. The microstructure of the composite powder, the dispersion of B4C particles in aluminium matrix, as well as the quality of Al/B4C interface after cryomilling were investigated using transmission electron microscopy and high-resolution transmission electron microscopy, respectively. Results revealed that morphology evolution could be attributed not only to the coupled effects of the plastic deformation, severe comminution and cold welding of the composite powder during cryomilling, but also to the ‘bridge-making’ mechanism of the nanometric B4C particles immersed in the liquid nitrogen. The average size of aluminium grains in the composite powder milled for 2 hours was measured as 100–200 nm. Furthermore, the homogeneous distribution of the nanometric B4C in aluminium and the clean metallurgical Al/B4C interfaces were also achieved within the composite powders prepared in this work.

Wear properties of Al–Al2O3/TiB2 surface hybrid composite layer prepared by friction stir process

In this study, surface hybrid composite was fabricated on Al6061 base sheets using friction stir processing (FSP). Samples were subjected to various numbers of FSP passes from one to four with Al2O3/TiB2 powder. Influence of number of FSP passes was studied on distribution of Al2O3/TiB2 particles in aluminium matrix, microstructure, hardness, and wear properties of specimens. The results showed that increase in the number of passes causes a more uniform dispersion of composite particles and thus, decreases particles clustering. In addition, an increase in the number of FSP passes was found to decrease the matrix grain size of the surface hybrid composite. It was observed that the hardness increased as the number of passes increased due to presence and pinning effect of hard Al2O3/TiB2 particles. Also, at higher number of passes, the surface hybrid composite wear resistance was increased.

TEM Investigations of Aluminium Composite Materials Reinforced with Ti(C,N) Ceramic Particles

Investigations of composite materials based on EN AW-AlCu4Mg1 (A) aluminium alloy reinforced with Ti (C,N) particles with weight ratios of 5, 10, and 15% are presented in this paper. The metallographic investigations of composite materials show banding of the reinforcing particles in aluminium matrix after the performed extrusion process. The structure observed in composites materials is oriented parallel to the extrusion direction. The amount of reinforcement particles Ti (C,N) has influence on the mechanical properties of the obtained composite materials. The increase of hardness is observed with the growth of the amount of reinforcement particles. Hardness increased from 89 HV1 for the material without the reinforcing phase to 143 HV1 for 15% of the Ti (C,N) reinforced material.Based on the microstructural investigations of the obtained composite materials, the uniform distribution of the reinforcing particles in the aluminium matrix was also revealed in the obtained structure.

Tribological Properties and a Wear Model of Aluminium Matrix Composites - SiC Particles Designed for Metal Forming

Abstract Aluminium based metal matrix composites are well known for their good wear resistance, high specific strength, stiffness and hardness. They have been applied in the aerospace, military and, especially, in the automotive industries. This paper presents the results of tests with regard to the application of a mixture of particles in aluminium matrix (AlCu2SiMn) composites where a mixture of SiC ceramic particles was used. The aim of the research was to determine the tribological properties as well as the phenomena and mechanisms which accompany the tribological wear of composites under dry friction conditions. The tribological investigations were conducted on a pin-on-block tester. The results of the tests show the composite obtained can be applied for sliding elements. Based on microscopic examinations and profilometry of the composites AlCu2SiMn+SiC surfaces at interaction the relationship between the size of reinforcing particles and the geometry of the surface layer of the composite was described. The study made it possible to develop a model of tribological wear of composites depending on the size of reinforcing particles.

INVESTIGATION OF STRUCTURE AND PHASE COMPOSITION OF POWDER ALUMINIUM-PHOSPHORUS MASTER ALLOYS

There were developed powder aluminium-phosphorus master alloys for modification of hypereutectic silumins. There was se-lected the best performance processing of powder mixes in the high-energy planetary mill that ensured minimum losses of feed stock and microstructure with uniform and disperse distribution of the proeutectoid constituents’ particles in aluminium matrix. By means of X-ray diffraction study was investigated phase composition of obtained master alloys. There was demonstrated high efficiency of the modification of hypereutectic silumins Al–17wt.%Si by alloying of phosphorus (0,008 wt.%) obtained master alloys.

Hardness and Wear Resistance of ZrO2 Nano Particle Reinforced Al Nanocomposites Produced by Powder Metallurgy

Nano particle reinforced Aluminium Nanocomposites are produced using Zirconium dioxide (n-ZrO2). Nano particles produced by solution combustion method. Urea is used as fuel and then reinforcing into Aluminium matrix in different percentages by weight using the powder metallurgy technique. The specimens prepared are tested for their hardness and microstructure. The above mentioned properties were chosen due to the reinforcement added (n-ZrO2) which is known to have good toughness and hardness among other structural properties at room temperature. The composites are tested for wear resistance by using pin on disc wear testing machine. Study of Wear mechanisms, Microstructure were performed on sintered specimens. Microstructure revealed near uniform distribution of n-ZrO2 particles with slight agglomeration. The microstructure also revealed good interfacial bond between matrix and n-ZrO2 particles. Incorporation of n-ZrO2 particles in aluminium matrix can lead to the production of aluminium composites with improved hardness and wear resistance. These composites can find applications in automotive components like pistons, cylinder liners and connecting rods.