Phase evolution and microstructure of highJcSiC doped MgB2fabricated by hot pressing

2009 ◽  
Vol 22 (7) ◽  
pp. 075014 ◽  
Author(s):  
B Qu ◽  
X D Sun ◽  
J-G Li ◽  
Z M Xiu ◽  
C P Xue
Keyword(s):  
Hot Pressing ◽  
Phase Evolution

Investigation of γ-Alon Structural Evolution during Sintering and Hot-Pressing

2009 ◽  
Vol 409 ◽  
pp. 313-316 ◽  
Author(s):  
Dariusz Zientara ◽  
Mirosław M. Bućko ◽  
Jerzy Lis
Keyword(s):  
Hot Pressing ◽  
Structural Changes ◽  
Structural Evolution ◽  
Phase Evolution ◽  
Pressureless Sintering ◽  
Low Dielectric ◽  
High Temperature Mechanical Properties ◽  
Thermal Expansion Coefficients ◽  
Infrared Wavelengths ◽  
Aluminium Oxynitride

Dense polycrystalline aluminium oxynitride with spinel structure, -alon, is noted for its excellent thermal properties, high-temperature mechanical properties, low dielectric constant, thermal expansion coefficients and intrinsic transparency extending from ultraviolet to mid-infrared wavelengths. The dense materials were made by reactive pressureless sintering or hot-pressing of the SHS derived powders. Powders were synthesized from mixtures of aluminium and corundum powders of different proportions. The products of the SHS synthesis were composed mostly of -alon and in lesser extend of aluminium nitride. Ground powders were pressureless sintered at temperatures of 1800-2100°C for 2-6hs as well as hot-pressed at 1750-1950°C for 1 h under 25 MPa in nitrogen flow. The present work is focused on phase evolution of -alon materials during pressureless sintering and hot-pressing. The structural changes of -alon, a Al2O3 and AlN were also examined.

Fabrication of Layered-Ternary Ti3AlC2 Ceramics by High Energy Milling and Hot Pressing Sintering

2010 ◽  
Vol 105-106 ◽  
pp. 207-209 ◽  
Author(s):  
Jian Feng Zhu ◽  
Guo Quan Qi ◽  
Bo Bo Liu ◽  
Fen Wang
Keyword(s):  
High Temperature ◽  
Hot Pressing ◽  
Single Phase ◽  
Phase Evolution ◽  
High Energy ◽  
Bulk Ceramic ◽  
High Energy Milling ◽  
Hot Pressing Sintering ◽  
Milled Powders

Fully dense and single-phase Ti3AlC2 bulk ceramic was successfully fabricated by a high energy milling and hot-pressing with Ti, C and Al as starting materials. The details of reaction and phase evolution in high energy milling and hot pressing sintering were investigated. The results show that most of the starting materials transform to Ti-Al intermetallics and TiC in high-energy milling. The as milled powders react into Ti2AlC firstly in hot pressing sintering. When the temperature raise high enough, the Ti2AlC transform to Ti3AlC2. The content of aluminum is higher than that in the theoretical composition, which is attributing to the volatilization of Al at high temperature.

Microstructural Evolution during Mechanical Alloying and Hot Pressing of a Powder Blend of Aluminium and 316 Stainless Steel

2006 ◽  
Vol 114 ◽  
pp. 211-218
Author(s):  
A. Samanta ◽  
P.P. Chattopadhyay ◽  
Witold Łojkowski ◽  
Stanislaw Gierlotka ◽  
Hans Jorg Fecht ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Property ◽  
Stainless Steel ◽  
Hot Pressing ◽  
Milled Powder ◽  
Phase Evolution ◽  
Xrd Analysis ◽  
High Energy ◽  
Nanocrystalline Powders ◽  
Powder Blend

The paper examines the phase evolution in blends consisting of different proportions of stainless steel (SS316) and Al (0, 25, 65 and 85 wt. %) powders during high-energy ball milling by x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy. An attempt has also been made to study the mechanical property of the bulk samples obtained by hot pressing the ball milled powder blend at suitable a temperature and pressure. The results of microstructural changes and mechanical property and the ability of consolidation of the amorphous/nanocrystalline powders by high-pressure techniques to develop engineering components has been discussed and highlighted.

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 hot pressing on the modulated structure of Zr0.98Sn0.02TiO4

1998 ◽  
Vol 77 (4) ◽  
pp. 1033-1037 ◽  
Author(s):  
Y. Park, S. A. Song H., G. Kim
Keyword(s):  
Hot Pressing ◽  
Modulated Structure

Chemical Availability of Bromide Dictates CsPbBr3 Nanocrystal Growth

2019 ◽  
Author(s):  
Je-Ruei Wen ◽  
Benjamin Roman ◽  
Freddy Rodriguez Ortiz ◽  
Noel Mireles Villegas ◽  
Nicholas Porcellino ◽  
...  
Keyword(s):  
Reaction Time ◽  
Growth Mechanism ◽  
Chemical Control ◽  
Critical Role ◽  
Phase Evolution ◽  
Detailed Understanding ◽  
Semiconductor Nanocrystal ◽  
Nanocrystal Growth ◽  
Chemical Availability

Lack of detailed understanding of the growth mechanism of CsPbBr3 nanocrystals has hindered sophisticated morphological and chemical control of this important emerging optoelectronic material. Here, we have elucidated the growth mechanism by slowing the reaction kinetics. When 1-bromohexane is used as an alternative halide source, bromide is slowly released into the reaction mixture, extending the reaction time from ~3 seconds to greater than 20 minutes. This enables us to monitor the phase evolution of products over the course of reaction, revealing that CsBr is the initial species formed, followed by Cs4PbBr6, and finally CsPbBr3. Further, formation of monodisperse CsBr nanocrystals is demonstrated in a bromide-deficient and lead-abundant solution. The CsBr can only be transformed into CsPbBr3 nanocubes if additional bromide is added. Our results indicate a fundamentally different growth mechanism for CsPbBr3 in comparison with more established semiconductor nanocrystal systems and reveal the critical role of the chemical availability of bromide for the growth reactions.<br>

Wear Characteristics of Circular cBN/Diamond Saws Produced by Hot Pressing

2014 ◽  
Vol 56 (3) ◽  
pp. 213-217 ◽  
Author(s):  
Serkan Islak ◽  
Durmuş Kır ◽  
Halis Çelik
Keyword(s):  
Hot Pressing ◽  
Wear Characteristics
Sign in / Sign up

Export Citation Format

Share Document