scholarly journals MWCNT-Reinforced AA7075 Composites: Effect of Reinforcement Percentage on Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 969
Author(s):  
Iria Feijoo ◽  
Gloria Pena ◽  
Marta Cabeza ◽  
M. Julia Cristóbal ◽  
Pilar Rey
Keyword(s):  
Multiwall Carbon Nanotubes ◽  
Tensile Tests ◽  
High Energy ◽  
Milling Process ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Strip Shape ◽  
The Matrix ◽  
Micro Deformation ◽  
Scherrer Formula

Metal–matrix composites (MMC) of aluminium alloy 7075 (AA7075) containing 1 wt.% and 0.5 wt.% multiwall carbon nanotubes (MWCNTs) were developed by powder metallurgy, using a high energy ball milling (HEBM) process for dispersion of the MWCNTs. The powder of the AA7075-MWCNT obtained was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microstructural changes produced during the milling process, such as the modification of the crystallite size, as well as the micro-deformation of the matrix crystal lattice, were determined using the Scherrer formula. After consolidation into a strip shape using the hot powder extrusion (HPE) process at 500 °C, no porosity was detected and a fine homogeneous dispersion of the reinforcement into the matrix was obtained. After performing a 0.2 HV test and tensile tests in the extruded profiles of both composites, a better combination of properties was found in samples of AA7075-0.5 wt.% MWCNT, with the increase in measured ductility being especially remarkable.

Effect of Milling Speed on the Synthesis of In-Situ Cu-25 Vol. % WC Nanocomposite by Mechanical Alloying

2012 ◽  
Vol 59 (2) ◽  
Author(s):  
Nurulhuda Bashirom ◽  
Nurzatil Ismah Mohd Arif
Keyword(s):  
Stainless Steel ◽  
Mechanical Alloying ◽  
Weight Ratio ◽  
High Energy ◽  
Milling Process ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
The Matrix ◽  
Steel Balls

This paper presents a study on the effect of milling speed on the synthesis of Cu-WC nanocomposites by mechanical alloying (MA). The Cu-WC nanocomposite with nominal composition of 25 vol.% of WC was produced in-situ via MA from elemental powders of copper (Cu), tungsten (W), and graphite (C). These powders were milled in the high-energy “Pulverisette 6” planetary ball mill according to composition Cu-34.90 wt% W-2.28 wt% C. The powders were milled in different milling speed; 400 rpm, 500 rpm, and 600 rpm. The milling process was conducted under argon atmosphere by using a stainless steel vial and 10 mm diameter of stainless steel balls, with ball-to-powder weight ratio (BPR) 10:1. The as-milled powders were characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). XRD result showed the formation of W2C phase after milling for 400 rpm and as the speed increased, the peak was broadened. No WC phase was detected after milling. Increasing the milling speed resulted in smaller crystallite size of Cu and proven to be in nanosized. Based on SEM result, higher milling speed leads to the refinement of hard W particles in the Cu matrix. Up to the 600 rpm, the unreacted W particles still existed in the matrix showing 20 hours milling time was not sufficient to completely dissolve the W.

Ni3Fe Mechanically Alloyed: “Shock Mode” versus “Friction Mode”

2011 ◽  
Vol 672 ◽  
pp. 153-156 ◽  
Author(s):  
Virgiliu Călin Prică ◽  
Traian Florin Marinca ◽  
Florin Popa ◽  
Ionel Chicinaş
Keyword(s):  
Grain Size ◽  
High Energy ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Grain Sizes ◽  
Friction Mode ◽  
Energy Ball ◽  
Scherrer Formula ◽  
Mode Versus

Ni3Fe powder has been obtained by high energy ball milling from elemental powders. We used two extreme conditions for milling: “friction mode” – friction between powder and ball/vial– and “shock mode” – direct impact of ball to powders. The influence of milling mode - friction and shock – was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was observed that the Ni3Fe grain size obtained by “friction mode” after 30 hours of milling was around 10 nm. For “shock mode” milling the average grain sizes was around 17 nm after 20 hours. The grain size was calculated using Williamson-Hall formula for both, “shock mode” and “friction mode” of milled powders and Scherrer formula for annealed powders. The powders were subjected to an annealing (30 min. at 350 °C) in order to eliminate the internal stress accumulated to the milling process and to finish the Ni3Fe phase formation.

Production and Structural Characterization of Some Magnesium Matrix Composites Reinforced with Amorphous/Nanocrystalline NiTi Particulates

2019 ◽  
Vol 69 (12) ◽  
pp. 3503-3507
Author(s):  
Mariana Ciurdas ◽  
Daniela Alina Necsulescu ◽  
Cristian Mircea Pantilimon ◽  
Vasile Ion ◽  
Magdalena Galatanu ◽  
...  
Keyword(s):  
High Energy ◽  
Amorphous Structure ◽  
Planetary Mill ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Magnesium Matrix ◽  
Magnesium Matrix Composites ◽  
The Matrix ◽  
Titanium Powders

Two mixtures of elemental nickel and titanium powders in atomic proportions of 50% Ni + 50% Ti and 32% Ni + 68% Ti, respectively, were ground for 40 hours in a high energy planetary mill. In the case of the first mixture, the mechanical alloying was totally produced, while for the second, the alloying was partial. In both mixtures, qualitative X-ray diffraction phase analysis revealed the presence of metastable phases, such as Ni HC and NiTi- R-phase. Also, the equiatomic mixture is characterized by a partially amorphous structure. 10% of each type of mixture submitted to milling was used as reinforcing element in the form of particulates for two magnesium matrix composites. They were obtained by sintering in the plasma at 590�C. In the case of the reinforced with the second mixture composite, the production of new phases other than the matrix and those present in the mixture of nickel and titanium powders after milling were recorded. The electron microscopy images of the two composites have resistant, free of micropores or microcracks matrix / particulates interfaces. The Mg-10% (32 at% Ni + 68 at% Ti) composite is characterized by Vickers hardness higher than that of the composite reinforced with the equiatomic mixture.

scholarly journals Manufacture and characterization of aa6061 aluminum alloy metal matrix composites with ceramic particulate reinforcement

2021 ◽  
pp. 46875-46883
Keyword(s):  
Metal Matrix ◽  
High Energy ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Particulate Reinforcement ◽  
Aluminum Metal Matrix Composite ◽  
The Matrix ◽  
Alloy Metal

The work’s main objective was the manufacture of an AA6061 aluminum metal matrix composite reinforced with ceramics reinforcements of: aluminum oxide, silicon carbide, aluminum nitride and silicon nitride, through the powder metallurgy technique. The powders were subjected to high energy milling in a SPEX type vibrating mill. Thereafter, a cold uniaxial compactation was made and then the compacts were hot extruded. The powders were subjected to characterization using X-ray diffraction and laser diffraction granulometry. The extruded were characterized by scanning electron microscopy, energy dispersive spectroscopy and had their microhardness evaluated. The characteri-zation showed: the reinforcements’ addition in the matrix contributed to an acceleration of powders’ grinding; the reinforced samples had a higher microhardness than the unreinforced; it was observed that greater milling times and reinforcement’s addition increased the composites’ microhardness.

scholarly journals Effect of Vanadium Reinforcement on the Microstructure and Mechanical Properties of Magnesium Matrix Composites

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 806
Author(s):  
Liqing Sun ◽  
Shuai Sun ◽  
Haiping Zhou ◽  
Hongbin Zhang ◽  
Gang Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Milling Process ◽  
Mg Alloy ◽  
Matrix Composites ◽  
Magnesium Matrix Composites ◽  
Pinning Effect ◽  
Average Grain Size ◽  
The Matrix ◽  
Hot Press Sintering

In this work, vanadium particles (VP) were utilized as a novel reinforcement of AZ31 magnesium (Mg) alloy. The nanocrystalline (NC) AZ31–VP composites were prepared via mechanical milling (MM) and vacuum hot-press sintering. During the milling process, the presence of VP contributed to the cold welding and fracture mechanism, resulting in the acceleration of the milling process. Additionally, increasing the VP content accelerated the grain refinement of the matrix during the milling process. After milling for 90 h, the average grain size of AZ31-X wt % Vp (X = 5, 7.5, 10) was refined to only about 23 nm, 19 nm and 16 nm, respectively. In the meantime, VP was refined to sub-micron scale and distributed uniformly in the matrix, exhibiting excellent interfacial bonding with the matrix. After the sintering process, the average grain size of AZ31-X wt % VP (X = 5, 7.5, 10) composites still remained at the NC scale, which was mainly caused by the pinning effect of VP. Besides that, the porosity of the sintered composites was no more than 7.8%, indicating a good densification effect. As a result, there was little difference between the theoretical and real density. Compared to as-cast AZ31 Mg alloy, the microhardness of sintered AZ31-X wt % VP (X = 5, 7.5, 10) composites increased by 65%, 87% and 96%, respectively, owing to the strengthening mechanisms of grain refinement strengthening, Orowan strengthening and load-bearing effects.

scholarly journals Experimental Research on Bond Behaviour of Fabric Reinforced Cementitious Matrix Composites for Retrofitting Masonry Walls

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Fayu Wang ◽  
Nicholas Kyriakides ◽  
Christis Chrysostomou ◽  
Eleftherios Eleftheriou ◽  
Renos Votsis ◽  
...  
Keyword(s):  
Large Scale ◽  
Tensile Tests ◽  
Seismic Resistance ◽  
Matrix Composites ◽  
Bond Behaviour ◽  
Cementitious Matrix ◽  
The Matrix ◽  
Rc Frame Buildings ◽  
Direct Tensile ◽  
Fabric Reinforced Cementitious Matrix

AbstractFabric reinforced cementitious matrix (FRCM) composites, also known as textile reinforced mortars (TRM), an inorganic matrix constituting fibre fabrics and cement-based mortar, are becoming a widely used composite material in Europe for upgrading the seismic resistance of existing reinforced concrete (RC) frame buildings. One way of providing seismic resistance upgrading is through the application of the proposed FRCM system on existing masonry infill walls to increase their stiffness and integrity. To examine the effectiveness of this application, the bond characteristics achieved between (a) the matrix and the masonry substrate and (b) the fabric and the matrix need to be determined. A series of experiments including 23 material performance tests, 15 direct tensile tests of dry fabric and composites, and 30 shear bond tests between the matrix and brick masonry, were carried out to investigate the fabric-to-matrix and matrix-to-substrate bond behaviour. In addition, different arrangements of extruded polystyrene (XPS) plates were applied to the FRCM to test the shear bond capacity of this insulation system when used on a large-scale wall.

High-Energy Ball Milling and Sintering of Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B Powders Mixtures

2014 ◽  
Vol 802 ◽  
pp. 20-24 ◽  
Author(s):  
Lucas Moreira Ferreira ◽  
Luciano Braga Alkmin ◽  
Érika C.T. Ramos ◽  
Carlos Angelo Nunes ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Ball Milling ◽  
Weight Ratio ◽  
High Energy ◽  
Milling Process ◽  
Wet Milling ◽  
X Ray Diffraction ◽  
Heat Treated ◽  
Equilibrium Structures ◽  
Rotary Speed ◽  
Steel Balls

The milling process of elemental Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B (at-%) powder mixtures were performed in a planetary Fritsch P-5 ball mill using stainless steel vials (225 mL) and hardened steel balls (19 mm diameter). Ball-to-powder weight ratio of 10:1 and a rotary speed of 300 rpm were adopted, varying the milling time. Wet milling (isopropyl alcohol) for 20 more minutes was used to increase the yield powder in to the vial. Following the Ti-Ta-Si-B powders milled for 600 min were heat-treated at 1100°C for 1 h in order to obtain the equilibrium structures. The milled powders and heat-treated samples were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. Supersaturated Ti solid solutions were formed during ball milling of Ti-Ta-Si-B powders while that the Ti5Si3 phase was formed after milling for 620 min of the Ta-richer powder mixture only. The particles sizes were initially increased during the initial milling times, and the wet milling provided the yield powder into the vials. A large amount of pores was found in both the sintered samples which presented the formation of the TiSS,(ss-solid solution) Ti6Si2B and TiB.

scholarly journals Influence of ZnO addition and milling process on structure and conductivity of BaCe0.2Zr0.7Y0.1O3-δ ceramics

2021 ◽  
Vol 15 (3) ◽  
pp. 288-296
Author(s):  
Ana Ana Kaori de Oliveira Ouba ◽  
Adilson Chinelatto ◽  
Edson Grzebielucka ◽  
Kethlinn Ramos ◽  
Janaina Borcezi ◽  
...  
Keyword(s):  
Secondary Phase ◽  
Linear Shrinkage ◽  
High Energy ◽  
Milling Process ◽  
Sintering Aids ◽  
X Ray Diffraction ◽  
Sintering Aid ◽  
Secondary Phase Formation ◽  
Precursor Powders ◽  
Perovskite Lattice

Precursor powders for BaCe0.2Zr0.7Y0.1O3-?(BCZY27) ceramics were synthesized by a modified Pechinimethod and calcined at 900?C for 12 h. The calcined BCZY27 powders were milled in eccentric and in high energy mill with the addition of 2 and 4mol% ZnO as sintering aid. The effects of milling and sintering aids on the sinterability and electrical conductivity were studied. The linear shrinkage in thermomechanical analyses started at 1050?C for the BCZY27 with 4mol% ZnO processed in eccentric mill. Theoretical density above of 90%TD was obtained for the BCZY27 milled with 4mol% ZnO and sintered at 1400?C for 4h. X-ray diffraction analysis of the BCZY27 ceramics sintered at 1400?C confirmed the presence of BaCe0.2Zr0.7Y0.1O3-? and Y0.4Ce0.6O1.8 phases. The incorporation of Zn into perovskite lattice leads to the secondary phase formation. SEM and EDS analyses confirmed the presence of Y0.4Ce0.6O1.8 phase. The sintering was assisted by BaO-ZnO eutectic, which was reflected by the increase of activation energy values for grain boundary conduction. The milling processing did not affect the conductivity properties. The obtained BCZY27 dense sample has conductivity of 7.60 ? 10?3 S/cm at 500?C.

Microstructure and Oxidation Resistance of Mechanically Alloyed and Sintered Ni-Nb and Ni-Nb-Ta Alloys

2017 ◽  
Vol 899 ◽  
pp. 19-24
Author(s):  
Lucas Moreira Ferreira ◽  
Stephania Capellari Rezende ◽  
Antonio Augusto Araújo Pinto da Silva ◽  
Gael Yves Poirier ◽  
Gilberto Carvalho Coelho ◽  
...  
Keyword(s):  
Ball Milling ◽  
Oxidation Resistance ◽  
Energy Dispersive Spectrometry ◽  
High Energy ◽  
Milling Process ◽  
Ternary Alloys ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Static Oxidation ◽  
Energy Ball

The present work reports on the microstructure and oxidation resistance of Ni-25Nb, Ni-20Nb-5Ta and Ni-15Nb-10Ta alloys produced by high-energy ball milling and subsequent sintering. The sintered samples were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, energy dispersive spectrometry, and static oxidation tests. Homogeneous microstructures of the binary and ternary alloys indicated the major presence of the β-Ni3Nb compound as matrix, which dissolved large amounts of tantalum. Consequently, the β-Ni3Nb peaks moved toward the direction of smaller diffraction angles. Iron contamination lower than 6.7 at.-% was detected by EDS analysis, which were picked-up during the previous ball milling process. After the static oxidation tests (1100°C for 4 h) the sintered Ni-25Nb, Ni-20Nb-5Ta and Ni-15Nb-10Ta alloys presented mass gains of 31.5%, 30.5% and 28.8%, respectively. Despite the higher densification of the Ni-15Nb-10Ta alloy, the results suggested that the tantalum addition contributed to improve the oxidation resistance of the β-Ni3Nb compound.

SYNTHESIS OF NANO-CRYSTALLINE Cu-Cr ALLOY BY MECHANICAL ALLOYING

2012 ◽  
Vol 05 ◽  
pp. 496-501 ◽  
Author(s):  
S. SHEIBANI ◽  
S. HESHMATI-MANESH ◽  
A. ATAIE
Keyword(s):  
Mechanical Alloying ◽  
Structural Evolution ◽  
High Energy ◽  
Lattice Parameter ◽  
Control Agent ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Nano Crystalline ◽  
High Energy Ball Mill ◽  
Energy Ball

In this paper, the influence of toluene as the process control agent (PCA) and pre-milling on the extension of solid solubility of 7 wt.% Cr in Cu by mechanical alloying in a high energy ball mill was investigated. The structural evolution and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The solid solution formation at different conditions was analyzed by copper lattice parameter change during the milling process. It was found that both the presence of PCA and pre-milling of Cr powder lead to faster dissolution of Cr . The mean crystallite size was also calculated and showed to be about 10 nm after 80 hours of milling.

Sign in / Sign up

Export Citation Format

Share Document