Novel materials synthesis by mechanical alloying/milling

1998 ◽  
Vol 43 (3) ◽  
pp. 101-141 ◽  
Author(s):  
B. S. Murty ◽  
S. Ranganathan
1992 ◽  
Vol 271 ◽  
Author(s):  
Kenneth J. Shea ◽  
Douglas A. Loy ◽  
James H. Small

ABSTRACTThe first representatives of novel materials that contain five- and six-coordinate anionie silicon are reported. Linear (or cyclic) ionomers incorporating pentacovalent siliconate were synthesized by condensation of 1,2,4,5-tetrahydroxybenzene (THB) with alkyl and aryl trialkoxysilylanes. Network ionomers that incorporate pentacovalent siliconates were formed from THB and alkyl and aryl bistrialkoxysilanes. In addition, network ionomers with hexacoordinate silicon result from condensation of TEOS and THB. Spectroscopie evidence is presented to verify the identity of the novel structural features of these materials.


Author(s):  
Günther Thiele ◽  
Silke Santner ◽  
Stefanie Dehnen

AbstractThe formation and transformation of crystalline chalcogenido metalates in ionic liquids as solvents is discussed as a new synthetic approach for the generation of novel materials. A comparison to conventional solvothermal reactions, classical high-temperature syntheses and chemical solution based approaches in common is discussed.


2013 ◽  
Vol 550 ◽  
pp. 71-78
Author(s):  
Ahmed Haddad ◽  
Mohammed Azzaz

An investigation was conducted to explore the applicability of Eddy Current (EC) and magnetic techniques to characterize the formation and grains size variation during Mechanical Alloying (MA) and the formation of a new mixture due to the variation of crystallography parameters. The change in apparent density was attributable to the irregular particles of the metal powders. A series of Nanocrystalline (Fe65Co35)xAl1-x samples have been prepared using M.A based on planetary ball mill under several milling conditions. M.A is a non-equilibrium process for materials synthesis. The structural effects of MA of powders were investigated by X-Ray diffraction analysis, SEM, microwaves, hysteresis magnetic and Eddy Current technique. Consequently, a nanostructure alloy was obtained with an average grain size of 8 nm. Experimental results show that fine nanocrystalline alloy powders prepared by mechanical milling are very promising for microwave applications and it is suggested that Eddy current measurement technique is a useful tool for the characterization of nanocrystalline materials.


Author(s):  
G.E. Ice

The increasing availability of synchrotron x-ray sources has stimulated the development of advanced hard x-ray (E≥5 keV) microprobes. With new x-ray optics these microprobes can achieve micron and submicron spatial resolutions. The inherent elemental and crystallographic sensitivity of an x-ray microprobe and its inherently nondestructive and penetrating nature will have important applications to materials science. For example, x-ray fluorescent microanalysis of materials can reveal elemental distributions with greater sensitivity than alternative nondestructive probes. In materials, segregation and nonuniform distributions are the rule rather than the exception. Common interfaces to whichsegregation occurs are surfaces, grain and precipitate boundaries, dislocations, and surfaces formed by defects such as vacancy and interstitial configurations. In addition to chemical information, an x-ray diffraction microprobe can reveal the local structure of a material by detecting its phase, crystallographic orientation and strain.Demonstration experiments have already exploited the penetrating nature of an x-ray microprobe and its inherent elemental sensitivity to provide new information about elemental distributions in novel materials.


Author(s):  
T. E. Mitchell ◽  
P. B. Desch ◽  
R. B. Schwarz

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.


2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.


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