scholarly journals Effects of Mechanical Alloying on Sintering Behavior of Tungsten Carbide-Cobalt Hard Metal System

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Ahmet Ozan Gezerman ◽  
Burcu Didem Çorbacıoğlu
Keyword(s):  
Mechanical Alloying ◽  
Tungsten Carbide ◽  
Particle Surface ◽  
Experimental Studies ◽  
Hard Metal ◽  
Sintering Behavior ◽  
Alloyed Powder ◽  
Tungsten Carbides ◽  
Mechanically Alloyed ◽  
Particle Surface Area

During the last few years, efforts have been made to improve the properties of tungsten carbides (WCs) by preparing composite materials. In this study, we prepared WC particles by mechanical alloying and investigated the effects of mechanical alloying conditions, such as mechanical alloying time and mechanically alloyed powder ratio, on the properties of 94WC-6Co. According to experimental studies, increasing the mechanical alloying time causes an increase in the density of tungsten carbide samples and a decrease of crystal sizes and inner strength of the prepared materials. With the increase of mechanical alloying time, fine particle concentrations of tungsten carbide samples have increased. It is observed that increasing the mechanical alloying time caused a decrease of the particle surface area of tungsten carbide samples. Besides, the amount of specific phases such as Co3W3C and Co6W6C increases with increasing mechanical alloying time. As another subject of this study, increasing the concentration of mechanically alloyed tungsten carbides caused an increase in the densities of final tungsten carbide materials. With the concentrations of mechanically alloyed materials, the occurrence of Co6W6C and Co3W3C phases and the increase of crystallization are observed.

Microstructure of mechanically alloyed and hot-pressed Al5CuZr2

1990 ◽  
Vol 48 (4) ◽  
pp. 970-971
Author(s):  
T. E. Mitchell ◽  
P. B. Desch ◽  
R. B. Schwarz
Keyword(s):  
Mechanical Alloying ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Rapid Quenching ◽  
Hardened Steel ◽  
Alloyed Powder ◽  
Ion Milling ◽  
Mechanical Grinding ◽  
Mechanically Alloyed ◽  
Steel Container

Al3Zr has the highest melting temperature (1580°C) among the tri-aluminide intermetal1ics. When prepared by casting, Al3Zr forms in the tetragonal DO23 structure but by rapid quenching or by mechanical alloying (MA) it can also be prepared in the metastable cubic L12 structure. The L12 structure can be stabilized to at least 1300°C by the addition of copper and other elements. We report a TEM study of the microstructure of bulk Al5CuZr2 prepared by hot pressing mechanically alloyed powder.MA was performed in a Spex 800 mixer using a hardened steel container and balls and adding hexane as a surfactant. Between 1.4 and 2.4 wt.% of the hexane decomposed during MA and was incorporated into the alloy. The mechanically alloyed powders were degassed in vacuum at 900°C. They were compacted in a ram press at 900°C into fully dense samples having Vickers hardness of 1025. TEM specimens were prepared by mechanical grinding followed by ion milling at 120 K. TEM was performed on a Philips CM30 at 300kV.

Effect of Aluminum on Fabrication of Ti3SiC2 by Mechanical Alloying and Spark Plasma Sintering

2007 ◽  
Vol 336-338 ◽  
pp. 1065-1068
Author(s):  
Song Zhe Jin ◽  
Bao Yan Liang ◽  
Jing Feng Li ◽  
Li Li
Keyword(s):  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
High Purity ◽  
Trace Amount ◽  
High Energy ◽  
Alloyed Powder ◽  
Mechanically Alloyed ◽  
Starting Mixture ◽  
Plasma Sintering ◽  
Spark Plasma

In the present study, we fabricated high purity and electrically machinable Ti3SiC2 ceramics by mechanical alloying and subsequent spark plasma sintering. The effect of a trace amount of Al on these synthesis processes was examined. Our results showed that Ti3SiC2 could be synthesized by high energy milling. Spark plasma sintering of mechanically alloyed powder at the temperatures of 1000-1200°C produced nearly single-phased Ti3SiC2 materials. The purity of the sintered Ti3SiC2 bulk was remarkably increased by addition of a small amount of Al. Ti3SiC2 with a purity of 99.3 wt% and a relative density of 98.9% was obtained by mechanical alloying and subsequent spark plasma sintering from a starting mixture composed of n(Ti) : n(Si) : n(Al) : n(c) = 3 : 1 : 0.2 : 2 at 1100°C.

scholarly journals Synthesis of Intermetallics in Fe-Al-Si System by Mechanical Alloying

Metals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 20 ◽  
Author(s):  
Kateřina Nová ◽  
Pavel Novák ◽  
Filip Průša ◽  
Jaromír Kopeček ◽  
Jaroslav Čech
Keyword(s):  
Mechanical Alloying ◽  
High Energy ◽  
Sintering Behavior ◽  
Mechanically Alloyed ◽  
Silicon Alloys ◽  
High Temperature Mechanical Properties ◽  
Plasma Sintering ◽  
Initial Stage ◽  
Feal Phase ◽  
Spark Plasma

Fe-Al-Si alloys have been recently developed in order to obtain excellent high-temperature mechanical properties and oxidation resistance. However, their production by conventional metallurgical processes is problematic. In this work, an innovative processing method, based on ultra-high energy mechanical alloying, has been tested for the preparation of these alloys. It has been found that the powders of low-silicon alloys (up to 10 wt. %) consist of FeAl phase supersaturated by Si after mechanical alloying. Fe2Al5 phase forms as a transient phase at the initial stage of mechanical alloying. The alloy containing 20 wt. % of Si and 20 wt. % of Al is composed mostly of iron silicides (Fe3Si and FeSi) and FeAl ordered phase. Thermal stability of the mechanically alloyed powders was studied in order to predict the sintering behavior during possible compaction via spark plasma sintering or other methods. The formation of Fe2Al5 phase and Fe3Si or Fe2Al3Si3 phases was detected after annealing depending on the alloy composition. It implies that the powders after mechanical alloying are in a metastable state; therefore, chemical reactions can be expected in the powders during sintering.

Quantities Directly Measurable by Scattering

2018 ◽  
Author(s):  
Eaton E. Lattman ◽  
Thomas D. Grant ◽  
Edward H. Snell
Keyword(s):  
Molecular Weight ◽  
Particle Shape ◽  
Particle Surface ◽  
Scattering Data ◽  
Radius Of Gyration ◽  
Particle Volume ◽  
Particle Surface Area ◽  
Scattering Angle ◽  
Particle Dimension ◽  
Maximum Particle

In this chapter we note that solution scattering data can be divided into four regions. At zero scattering angle, the scattering provides information on molecular weight of the particle in solution. Beyond that, the scattering is influenced by the radius of gyration. As the scattering angle increases, the scattering is influenced by the particle shape, and finally by the interface with the particle and the solution. There are a number of important invariants that can be calculated directly from the data including molecular mass, radius of gyration, Porod invariant, particle volume, maximum particle dimension, particle surface area, correlation length, and volume of correlation. The meaning of these is described in turn along with their mathematical derivations.

Effect of Small Iron, Chromium and Boron Additions as Alloying Elements on Microstructure and Mechanical Properties of Ni3Al

2007 ◽  
Vol 23 ◽  
pp. 123-126
Author(s):  
Radu L. Orban ◽  
Mariana Lucaci
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Room Temperature ◽  
Alloying Elements ◽  
Alloyed Powder ◽  
Mechanically Alloyed ◽  
Powder Mixtures ◽  
B Additions ◽  
Strength And Ductility ◽  
Iron Chromium

This paper investigates the effect of Fe, Cr and B additions, in small proportions, as alloying elements in Ni3Al with the purpose to reduce its intrinsic fragility and extrinsic embrittlement and to enhance, in the same time, its mechanical properties. It represents a development of some previous research works of the authors, proving that Ni3Al-Fe-Cr-B alloys obtained by reactive synthesis (SHS) starting from Mechanically Alloyed powder mixtures have superior both room temperature tensile strength and ductility, and compression ones at temperatures up to 800 °C, than pure Ni3Al. These create premises for their using as superalloys substitutes.

New Fe-Ni Based Metal-Metalloid Glassy Alloys Prepared by Mechanical Alloying and Rapid Solidification

1996 ◽  
Vol 455 ◽  
Author(s):  
J. J. Suñol ◽  
M. T. Clavaguera-Mora ◽  
N. Clavaguera ◽  
T. Pradell
Keyword(s):  
Mechanical Alloying ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Magnetic Interaction ◽  
Processing Route ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
Glassy Alloys ◽  
Rapidly Solidified ◽  
Thermal Stability Of

ABSTRACTMechanical alloying and rapid solidification are two important routes to obtain glassy alloys. New Fe-Ni based metal-metalloid (P-Si) alloys prepared by these two different processing routes were studied by differential scanning calorimetry and transmission Mössbauer spectroscopy. Mechanical alloyed samples were prepared with elemental precursors, and different nominal compositions. Rapidly solidified alloys were obtained by melt-spinning. The structural analyses show that, independent of the composition, the materials obtained by mechanical alloying are not completely disordered whereas fully amorphous alloys were obtained by rapid solidification. Consequently, the thermal stability of mechanically alloyed samples is lower than that of the analogous material prepared by rapid solidification. The P/Si ratio controls the magnetic interaction of the glassy ribbons obtained by rapid solidification. The experimental results are discussed in terms of the degree of amorphization and crystallization versus processing route and P/Si ratio content.

scholarly journals Effect of Milling Parameters on the Development of a Nanostructured FCC–TiNb15Mn Alloy via High-Energy Ball Milling

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1225
Author(s):  
Cristina García-Garrido ◽  
Ranier Sepúlveda Sepúlveda Ferrer ◽  
Christopher Salvo ◽  
Lucía García-Domínguez ◽  
Luis Pérez-Pozo ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Ball Mill ◽  
Milling Time ◽  
High Energy ◽  
Planetary Mill ◽  
Nominal Composition ◽  
Mechanically Alloyed ◽  
Milling Parameters ◽  
Energy Ball ◽  
Full Conversion

In this work, a blend of Ti, Nb, and Mn powders, with a nominal composition of 15 wt.% of Mn, and balanced Ti and Nb wt.%, was selected to be mechanically alloyed by the following two alternative high-energy milling devices: a vibratory 8000D mixer/mill® and a PM400 Retsch® planetary ball mill. Two ball-to-powder ratio (BPR) conditions (10:1 and 20:1) were applied, to study the evolution of the synthesized phases under each of the two mechanical alloying conditions. The main findings observed include the following: (1) the sequence conversion evolved from raw elements to a transitory bcc-TiNbMn alloy, and subsequently to an fcc-TiNb15Mn alloy, independent of the milling conditions; (2) the total full conversion to the fcc-TiNb15Mn alloy was only reached by the planetary mill at a minimum of 12 h of milling time, for either of the BPR employed; (3) the planetary mill produced a non-negligible Fe contamination from the milling media, when the highest BPR and milling time were applied; and (4) the final fcc-TiNb15Mn alloy synthesized presents a nanocrystalline nature and a partial degree of amorphization.

Influence of particle surface area on the toxicity of insoluble manganese dioxide dusts

1997 ◽  
Vol 71 (12) ◽  
pp. 725-729 ◽  
Author(s):  
Dominique Lison ◽  
Cécile Lardot ◽  
François Huaux ◽  
Giovanna Zanetti ◽  
Bice Fubini
Keyword(s):  
Manganese Dioxide ◽  
Surface Area ◽  
Particle Surface ◽  
Particle Surface Area
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