scholarly journals Evidence for self-sustained MoSi2 formation during room-temperature high-energy ball milling of elemental powders

1993 ◽  
Vol 8 (8) ◽  
pp. 1836-1844 ◽  
Author(s):  
E. Ma ◽  
J. Pagán ◽  
G. Cranford ◽  
M. Atzmon
Keyword(s):  
Ball Milling ◽  
Room Temperature ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Diffusion Couples ◽  
Compound Formation ◽  
Fine Grained ◽  
Energy Ball ◽  
High Temperature Reactions ◽  
Thin Film Diffusion

We present evidence indicating that rapid, self-sustained, high-temperature reactions play an important role in the formation of tetragonal MoSi2 during room-temperature high-energy ball milling of elemental powders. Such reactions appear to be ignited by mechanical impact in an intimate, fine-grained, Mo–Si physical mixture formed after an initial milling period. Under certain conditions, limited propagation of self-sustained reactions in these uncompacted powder mixtures renders the compound formation seemingly gradual in bulk-averaged analysis. It is suggested that this type of reaction is an important mechanism in the mechanical alloying of highly exothermic systems. Results are discussed in comparison with similar reactions we observed in ball-milled Al–Ni powders, with self-sustained combustion synthesis previously reported for Mo–Si powders, and with interfacial diffusional reactions in Mo–Si powders or thin-film diffusion couples.

Synchrotron X-ray Absorption Studies of Atomic-Level Alloying in Immiscible Mixtures

1998 ◽  
Vol 524 ◽  
Author(s):  
J.-H. He ◽  
P. J. Schilling ◽  
E. Ma
Keyword(s):  
Ball Milling ◽  
Room Temperature ◽  
High Energy ◽  
Atomic Level ◽  
High Energy Ball Milling ◽  
Edge Structure ◽  
X Ray ◽  
Energy Ball ◽  
Immiscible Mixtures ◽  
X Ray Absorption

ABSTRACTAn X-ray absorption beamline has been developed recently at the electron storage ring of the LSU Center for Advanced Microstructures and Devices. Using Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Structure (XANES), we have studied the local atomic environments in immiscible mixtures processed by high-energy ball milling, a mechanical alloying technique involving heavy deformation. By examining the local coordination and bond distances, it is concluded that atomic-level alloying can indeed be induced between Cu and Fe through milling at room temperature, forming substitutional fcc and bcc solid solutions. In addition to single-phase regions, a two-phase region consisting of fcc/bcc solutions has been found after milling at both room temperature and liquid nitrogen temperature. In contrast to the Cu-Fe system, solid solution formation is not detectable in milled Ag-Fe and Cu-Ta mixtures. This work demonstrates the power of synchrotron EXAFS/XANES experiments in monitoring nonequilibrium alloying on the atomic level. At the same time, the results provide direct experimental evidence of the capability as well as limitations of high-energy ball milling to form alloys in positive-heat-of-mixing systems.

Mechanical Alloying of Pet and Pet/Vectra Blends

1996 ◽  
Vol 461 ◽  
Author(s):  
C. M. Balik ◽  
C Bai ◽  
C.C Koch ◽  
R.J Spontak ◽  
C. K. Saw
Keyword(s):  
Molecular Weight ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Potential Method ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Weight Density ◽  
Energy Ball

ABSTRACTMechanical alloying represents a potential method for producing finely dispersed alloys of normally incompatible polymers. In this paper, PET and blends of PET with a Vectra thermotropic copolyester have been processed via high energy ball milling at room temperature (ambimilled) and at liquid nitrogen temperatures (cryomilled). Milled powders and compacted disks have been characterized using molecular weight, density and hardness measurements, aswell as DSC, WAXS, TEM and FTIR.

The Production of Ultra Fine Grained Al-SiCpComposites Produced via High Energy Ball Milling

2008 ◽  
Vol 45 (3) ◽  
pp. 136-149 ◽  
Author(s):  
Ismail Özdemir ◽  
Sascha Ahrens ◽  
Silke Mücklich ◽  
Bernhard Wielage
Keyword(s):  
Ball Milling ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Fine Grained ◽  
Energy Ball

Structural transformations of alumina by high energy ball milling

1993 ◽  
Vol 8 (11) ◽  
pp. 2985-2992 ◽  
Author(s):  
P.A. ZielińAski ◽  
R. Schulz ◽  
S. Kaliaguine ◽  
A. Van Neste
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Ball Milling ◽  
Room Temperature ◽  
High Energy ◽  
Structural Transformations ◽  
High Energy Ball Milling ◽  
Second Step ◽  
Transformation Rate ◽  
Energy Ball

Room temperature, high energy ball milling was applied to various transition aluminas (γ, K, χ), producing thermodynamically stable α-alumina–a phenomenon that could otherwise be achieved only by high temperature (1100–1200 °C) heat treatment. The transformation proceeds in two steps. The first one consists of rapid microstructural rearrangements with continuously increasing α-transformation rate. In the second step (1–2 h from the start), only relatively small changes in morphology are observed with a constant α-transformation rate. The rate is influenced only by the milling intensity. The presence or the absence of oxygen in the milling atmosphere has a large influence on the final surface area of α-alumina.

Room temperature hydrogen absorption by Mg and Mg TiFe nanocomposites processed by high-energy ball milling

2018 ◽  
Vol 43 (27) ◽  
pp. 12251-12259 ◽  
Author(s):  
R.A. Silva ◽  
R.M. Leal Neto ◽  
D.R. Leiva ◽  
T.T. Ishikawa ◽  
C.S. Kiminami ◽  
...  
Keyword(s):  
Ball Milling ◽  
Hydrogen Absorption ◽  
Room Temperature ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Energy Ball
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