Mechanical Milling of Prealloyed Cu-Cr Powders Prepared by Gas Atomization

2007 ◽  
Vol 26-28 ◽  
pp. 469-472 ◽  
Author(s):  
Hwan Kyun Yeo ◽  
Sang Ho Ahn ◽  
Kwan Hee Han
Keyword(s):  
Stainless Steel ◽  
Milled Powder ◽  
High Energy ◽  
Gas Atomization ◽  
Mechanically Alloyed ◽  
Attrition Milling ◽  
Nano Crystalline ◽  
State Regime ◽  
Small Grains ◽  
Steel Balls

In this study, we investigate the effects of high energy milling under Ar atmosphere on the morphology, size and microstructure of Cu-Cr alloy powders prepared by gas atomization. The attrition milling using stainless steel balls is performed up to 60 hrs. The observation by SEM and TEM shows apparent sequential changes of morphology and size of powders similar to those that are typical for mechanically alloyed elemental powders. Prolonged milling in the steady state regime produces a nano-crystalline structure, consisting of extremely small grains of 20 to 50 nm in size and finely dispersed Cr particles. It is also shown that the uptake of Fe from the stainless steel balls and vessel is appreciable. The microhardness of milled powder increases with the milling time, reaches its peak and then slightly decreases.

Ball milling for the formation of nanocrystalline intermetallic compounds from Ni-Ti elemental powders

2018 ◽  
Vol 27 (5-6) ◽  
Author(s):  
Pardeep Sharma
Keyword(s):  
Intermetallic Compounds ◽  
Milling Time ◽  
Lattice Strain ◽  
Research Work ◽  
High Energy ◽  
Mechanically Alloyed ◽  
Nano Crystalline ◽  
High Energy Ball Mill ◽  
Productive Process ◽  
Energy Ball

AbstractIn the present research work nickel (Ni) and titanium (Ti) elemental powder with an ostensible composition of 50% of each by weight were mechanically alloyed in a planetary high energy ball mill in diverse milling circumstances (10, 20, 30 and 60 h). The inspection exposed that increasing milling time leads to a reduction in crystallite size, and after 60 h of milling, the Ti dissolved in the Ni lattice and the NiTi (B2) phase was obtained. The lattice strain of ball milled mixtures augmented from 0.15 to 0.45 at 60 h milling. With increase in milling time the morphology of pre-alloyed powder changed from lamella to globular. Annealing of as-milled powders at 1100 K for 800 s led to the formation of NiTi (B19′), grain growth and the release of internal strain. The result indicated that this technique is a powerful and highly productive process for preparing NiTi intermetallic compounds with a nano-crystalline structure and appropriate morphology.

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.

Characterization of Binary Mg-Mn Alloy Synthesized through Mechanical Alloying: Effects of Milling Speed

2015 ◽  
Vol 1087 ◽  
pp. 479-483 ◽  
Author(s):  
Emee Marina Salleh ◽  
Sivakumar Ramakrishan ◽  
Zuhailawati Hussain
Keyword(s):  
Mechanical Alloying ◽  
Milled Powder ◽  
High Energy ◽  
Milling Process ◽  
Planetary Mill ◽  
Argon Atmosphere ◽  
Solid Solution Phase ◽  
Mechanically Alloyed ◽  
Bulk Properties ◽  
Solid State Route

In this work, the effect of the milling speed on the properties of biodegradable Mg-1Mn alloy prepared by mechanical alloying was investigated. The magnesium-based alloy was prepared in solid state route using a high energy planetary mill. A mixture of pure magnesium and manganese powder was mechanically alloyed for 5 hours in argon atmosphere. Milling process was performed at various rotational speeds in order to investigate milling speed effect (i.e., 100, 200, 300 and 400 rpm) on phase formation and bulk properties. The as-milled powder was uniaxially compacted by cold pressing under 400 MPa at room temperature and sintered in argon atmosphere at 500 °C for an hour. X-ray diffraction analysis indicated that a single α-Mg phase was formed in magnesium matrix after sintering process. An increase in milling speed up to 300 rpm resulted in an increase in density and hardness of the binary alloy. The changes of bulk properties of the Mg-Mn alloys were correlated to the formation of solid solution phase and a reduction of porosity which led to an increasing in densification.

Mechano-Chemical Effects of High-Energy Attrition Milling On The Bi2Sr2CaCu2Ox Superconductor

1992 ◽  
Vol 286 ◽  
Author(s):  
J. S. Luo ◽  
H. G. Lee ◽  
S. Sinha
Keyword(s):  
Crystal Size ◽  
Cold Work ◽  
Weight Ratio ◽  
Milled Powder ◽  
High Energy ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
Chemical Effects ◽  
Attrition Milling ◽  
Mechanical Attrition

ABSTRACTThe mechano-chemical effects of high-energy attrition milling on the microstructure evolution and superconducting properties of Bi2Sr2CaCu2Ox oxide powder were investigated by a combination of x-ray diffraction, scanning electron microscopy, and magnetization techniques. The powder was attrition-milled under an argon atmosphere, using a standard laboratory attritor with yittria-stabilized ZrO2 balls having a ball-to-powder weight ratio of ∼10:1. After selected time increments the mechanical attrition was interrupted and a small quantity of the milled powder was removed for analysis. The results indicate that (1) the crystal size decreases, (2) this decrease in crystal size is accompanied by degradation of crystallinity of the powder and accumulation of atomic-level strain, (3) the Bi-2212 phase decomposes under conditions of excessive deformation, and (4) the superconducting transition is depressed from 70 K to 60 K in the early stages of milling and completely vanishes upon prolonged deformation. The influence of defects (created during cold work) on the current carrying capacity is also presented and discussed.

Densification of Mechanically Alloyed Al5083-5wt% Y2O3 Nano Composite by Equal Channel Angular Pressing

2014 ◽  
Vol 592-594 ◽  
pp. 963-967
Author(s):  
Pravir Polly ◽  
K. Chandra Sekhar ◽  
Balasubramanian Ravisankar ◽  
S. Kumaran
Keyword(s):  
Equal Channel Angular Pressing ◽  
Single Phase ◽  
Milled Powder ◽  
High Energy ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Nano Composite ◽  
Angular Pressing ◽  
Energy Ball ◽  
Milled Powders

In the present work, Al-5083-5wt% nanoyttria powders were milled for 10, 20, 30 and 35 hrs in a high energy ball milling under optimised process parameters. The milled powders were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Milled powders exhibit nanocrystalline single phase after 10hrs of milling. Consolidation of 35 hrs milled powder was done by equal channel angular pressing (ECAP) through 90odie channel angle using route A upto three passes with and without back pressure and sintered under controlled environment. Density of ECAPed samples was measured using Archimedes principle. The density is 96% for the sample consolidated with backpressure after two passes after sintering.

Influence of microstructure and processing on mechanical properties of advanced Nb-silicide alloys

2012 ◽  
Vol 1516 ◽  
pp. 317-322 ◽  
Author(s):  
C. Seemüller ◽  
M. Heilmaier ◽  
T. Hartwig ◽  
M. Mulser ◽  
N. Adkins ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fine Particles ◽  
Phase Distribution ◽  
High Energy ◽  
Powder Injection ◽  
Gas Atomization ◽  
Alloyed Powder ◽  
Mechanically Alloyed ◽  
Metallurgical Processing ◽  
Formation Phase

ABSTRACTIn this study different powder metallurgical processing routes, commonly used for refractory metal based materials, were evaluated on their impact on mechanical properties of a multi-component Nb-20Si-23Ti-6Al-3Cr-4Hf (at.%) alloy. Powder was produced by gas-atomization or high energy mechanical alloying of elemental powders and then consolidated either by HIPing or powder injection molding (PIM). The PIM process requires fine particles. In this investigation powder batches of gas-atomized powder (< 25 μm) and mechanically alloyed powder (< 25 μm) were compacted via PIM. Fine (< 25 μm) and coarser (106-225 μm) particle fractions of gas-atomized powder were compacted via HIPing for comparison. Quantitative analysis of the resulting microstructures regarding porosity, phase formation, phase distribution, and grain size was carried out in order to correlate them with the ensuing mechanical properties such as compressive strength at various temperatures.

SYNTHESIS OF NANO CRYSTALLINE BARIUM HEXAFERRITE IN THE PRESENCE OF SALT CATALYSTS

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3120-3126
Author(s):  
ATEFEH HASSANIRAD ◽  
A. ATAIE ◽  
R. NIKKHAH-MOSHAEE
Keyword(s):  
Milled Powder ◽  
Barium Hexaferrite ◽  
High Energy ◽  
Synthesis Process ◽  
Oxide Ceramic ◽  
Nano Crystalline ◽  
High Energy Ball Mill ◽  
Powder Particles ◽  
Xrd Patterns ◽  
20 Nm

Nano crystalline barium hexaferrite, BaFe 12 O 19, were synthesized from mixture of barium acetate and iron oxide by conventional mixed oxide ceramic method. The mixture of precursors together with a 3wt% salt-catalyst (ammonium and sodium chlorides) was intensively milled by high energy ball mill for 10 hr. The influence of addition of catalyst on the synthesis process has been studied by XRD, SEM, DTA/TG and TEM techniques. Analysis of the XRD patterns indicates that salt-catalysts can strongly alter the morphology and phase composition of ball milled powder particles. Sample with 3wt% NH 4 Cl after milling for 10 hr and annealing at 900°C for 1 hr exhibited single phase barium hexaferrite with mean crystallite size of 20 nm.

Structural Evaluation of Ti-Cr-Si-B Powders Produced by High-Energy Ball Milling and Sintering

2017 ◽  
Vol 899 ◽  
pp. 499-504
Author(s):  
Luiz Otávio Vicentin Maruya ◽  
Paulo Atsushi Suzuki ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Ball Milling ◽  
Weight Ratio ◽  
High Energy ◽  
Milling Process ◽  
Wet Milling ◽  
Mechanically Alloyed ◽  
Structural Evaluation ◽  
Structural Applications ◽  
Rotary Speed ◽  
Steel Balls

Multicomponent Ti6Si2B-based alloys are potentially attractive for structural applications due to the low Ti6Si2B crystallographic anisotropy, and their oxidation resistance are higher than the Ti5Si3-based alloys. There is a limited amount of information on effect of alloying on stability of Ti6Si2B. The present work reports on the structural evaluation during ball milling and subsequent sintering of Ti-2Cr-22Si-11B and Ti-7Cr-22Si-11B (at-%) powders. The milling process was carried out in a planetary Fritsch P-5 ball mill under Ar atmosphere using hardened steel balls (19 mm diameter), stainless steel vials (225 mL), rotary speed of 300 rpm, and a ball-to-powder weight ratio of 10:1. Samples were collected after different milling times: 20, 60, 180, 300, 420 and 600 min. Addicional wet milling (isopropyl alcohol) for 20 more minutes was adopted to increase the yield powder into the vials. Following, the powders milled for 620 min were uniaxially compacted (20 MPa) in order to obtain cilinder green bodies with 10 mm diameter and subsequently sintered under vacuum at 1100°C for 240 min. The milled powders were characterized by X-ray diffraction, and scanning electron microscopy. The chromium addition have contributed to form a large amount of Ti6Si2B in the mechanically alloyed and sintered Ti-2Cr-22Si-11B and Ti-7Cr-22Si-11B alloys.

On the Phase Transformation in Mechanically Alloyed Ni-Nb and Ni-Ta and Ni-Nb-Ta Powders

2012 ◽  
Vol 727-728 ◽  
pp. 222-226 ◽  
Author(s):  
Ana Clara Ferraretto ◽  
Erika Coaglia Trindade Ramos ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Phase Transformation ◽  
Ball Milling ◽  
High Energy ◽  
Milling Process ◽  
Spontaneous Ignition ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Energy Ball ◽  
Rotary Speed ◽  
Steel Balls

This paper reports on the phase transformation during the preparation of Ni-25Nb, Ni-25Ta, Ni-20Nb-5Ta and Ni-15Nb-10Ta (at-%) powders by high-energy ball milling from elemental powders. The milling process was performed in a planetary ball milling using stainless steel balls and vials, rotary speed of 300rpm, and a ball-to-powder of 10:1. To minimize contamination and spontaneous ignition the powders were handled under argon atmosphere in a glove box. The milled powders were characterized by means of X-ray diffraction techniques. Results indicated that the Ni atoms were preferentially dissolved into the Nb (and/or Ta) lattice at the initial milling times, which contributed to change the relative intensity on the diffraction peaks. After the dissolution of Nb (and/or Ta) into the Ni lattice, the Ni peaks were moved to the direction of lower diffraction angles in Ni-25Nb, Ni-25Ta, Ni-20Nb-5Ta, Ni-15Nb-10Ta powders, indicating that the mechanical alloying was achieved. .

Study on the Oxidation Resistance of 316 Stainless Steel Nano-Powder Prepared by Ball-Milling Method

2009 ◽  
Vol 66 ◽  
pp. 151-154 ◽  
Author(s):  
Wen Yi Chen ◽  
Jian Zhou ◽  
Ying Liu
Keyword(s):  
Stainless Steel ◽  
Ball Milling ◽  
Oxidation Resistance ◽  
High Energy ◽  
Heating Rates ◽  
316 Stainless Steel ◽  
Nano Powder ◽  
Nano Crystalline ◽  
Milling Method ◽  
Dsc Method

316 stainless steel nano-grain powders were prepared by high-energy ball-milling method. The evolutions of grain size and microstructure of the stainless steel powders with the change of ball-milling conditions were investigated by XRD, SEM. DSC method was used to analyze the oxidation resistance of the powders after ball milling. The law of the change in oxidation weight gain and DSC oxidation peak of samples at the different heating rates were analyzed. Oxidation kinetics studies showed that the oxidant resistance of 316 stainless steel nano-crystalline powder was improved, the activation energy of oxidation reaction increased.

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