Dilatometric analysis on the sintering behavior of nanocrystalline W–Cu prepared by mechanical alloying

2002 ◽  
Vol 335 (1-2) ◽  
pp. 233-240 ◽  
Author(s):  
S.S Ryu ◽  
Y.D Kim ◽  
I.H Moon
Keyword(s):  
Mechanical Alloying ◽  
Sintering Behavior ◽  
Dilatometric Analysis

scholarly journals Influence of the Milling Time on Mechanical and Magnetic Properties of Cu90Co5Ni5 Alloy Obtained by Mechanical Alloying

2009 ◽  
Vol 423 ◽  
pp. 119-124 ◽  
Author(s):  
Marta López ◽  
M. Elena Gómez ◽  
David Reyes ◽  
K. Ramam ◽  
Ramalinga V. Mangalaraja ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Mechanical Alloying ◽  
Magnetic Particles ◽  
Milling Time ◽  
Copper Matrix ◽  
Milling Process ◽  
Sintering Behavior ◽  
Powder Samples ◽  
Xrd Patterns ◽  
Sintered Alloys

The structure, mechanical and magnetic properties of Cu90Co5Ni5 alloys produced by mechanical alloying and subsequent cold consolidation and sintering behavior, have been investigated. A system of small Co and Ni magnetic particles embedded in the non-magnetic copper matrix were prepared through a mechanical milling process by using a planetary ball mill under argon atmosphere for 20 to 60 h. The morphology and particles size, phase formation and chemical composition of the alloyed powder samples for each milling time were characterized by scanning electron microscope and powder X-ray diffraction techniques, respectively. After milling for 60 h, a supersaturated solid solution with coercive field Hc with maximum value of 235Oe was obtained. The continuous decreasing trend of saturation magnetization (Ms) with increasing of milling time can be explained by the reduction of copper oxide by (CoNi) oxide formation, confirmed by powder XRD patterns. The XRD analyses of the as-milled samples revealed that the Bragg peaks of FCC-Co changed partially to HCP-Co on increasing the milling time. Cu90Co5Ni5 powders cold consolidated and sintered at 650°C for 1h segregated mainly into two-phases of mixed (fcc,hc)-Co and fcc-CuNi. After sintering, the mechanical properties for 60h milling reached its optimum, 26HV in hardness corresponding to 250MPa as compressive strength. TEM microanalysis of sintered alloys revealed Co cluster of 2 to 5 nm in size separated each one by 10 to 20 nm in size. The variation of magnetic properties and its dependence on structural-precipitation change with milling time are discussed.

Spark Plasma Sintering Behavior of Fe-TiC Composite Materials Fabricated by Mechanical Alloying

2007 ◽  
Vol 544-545 ◽  
pp. 825-828 ◽  
Author(s):  
Ho Jung Cho ◽  
Sung Yeal Bae ◽  
In Shup Ahn ◽  
Dong Kyu Park
Keyword(s):  
High Temperature ◽  
Composite Materials ◽  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Cutting Tools ◽  
High Hardness ◽  
Sintering Behavior ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintering Properties

TiC-based cermets attract much attention because of their excellent wear-resistance, high hardness at high temperature, good chemical stability, superior thermal deformation resistance. Therefore, titanium carbide is mainly used for cutting tools, grinding wheels, coated cutting tips and coated steel tools. In this research, Fe-TiC composite materials were fabricated by spark plasma sintering (SPS) after mechanical alloying. TiH2 and graphite powders were used to synthesize TiC phase. In order to compare the properties of sintered materials using mixture powder (D’AE+TiH2+graphite), commercial TiC powder was mixed with Distaloy AE (D’AE) powder as a same mechanical alloying method. Then, the shape of each mixture powder (D’AE+TiH2+graphite, D’AE+TiC (commercial)) and sintering properties were compared. TiC phase was synthesized by self-propagating high-temperature synthesis (SHS) reaction during spark plasma sintering. It was confirmed by using X-ray diffraction (XRD). Energy dispersive spectrometry (EDS) and Scanning electron microscopy (SEM) were used to observe shape of mixture powders and also sintering properties were examined such as hardness, relative density. In case of sintered material for 10min holding time at 1373K after mechanical alloying for 1 hour with D’AE, TiH2 and graphite, it indicated higher hardness value 49HR-C than a case using D’AE and TiC powder.

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.

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.

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