scholarly journals Discovery of natural MgSiO3tetragonal garnet in a shocked chondritic meteorite

2016 ◽  
Vol 2 (3) ◽  
pp. e1501725 ◽  
Author(s):  
Naotaka Tomioka ◽  
Masaaki Miyahara ◽  
Motoo Ito
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Solid State ◽  
Electron Diffraction ◽  
Cooling Rate ◽  
Upper Bound ◽  
Cation Ordering ◽  
State Transformation ◽  
Solid State Transformation ◽  
Shock Temperature

MgSiO3tetragonal garnet, which is the last of the missing phases of experimentally predicted high-pressure polymorphs of pyroxene, has been discovered in a shocked meteorite. The garnet is formed from low-Ca pyroxene in the host rock through a solid-state transformation at 17 to 20 GPa and 1900° to 2000°C. On the basis of the degree of cation ordering in its crystal structure, which can be deduced from electron diffraction intensities, the cooling rate of the shock-induced melt veins from ~2000°C was estimated to be higher than 103°C/s. This cooling rate sets the upper bound for the shock-temperature increase in the bulk meteorite at ~900°C.

The Effects of Cooling Rate Upon Xdt m TiAl Weld Microstructure

1990 ◽  
Vol 194 ◽  
Author(s):  
Erica Robertson ◽  
Mary Ann Hill ◽  
Ricardo B. Schwarz
Keyword(s):  
Solid State ◽  
Cooling Rate ◽  
Volume Fraction ◽  
Mechanical Test ◽  
Test System ◽  
X Ray Diffraction ◽  
State Transformation ◽  
Solid State Transformation ◽  
X Ray ◽  
Weld Microstructure

AbstractFusion zone microstructures of an electron beam (EB) welded XDt m Ti–48at%Al + 6.5 vol% TiB2 alloy revealed plate-like precipitates which were absent in the base metal. The volume fraction of this phase increased with increasing cooling rate and correlated with increased weld cracking frequency. To determine whether this phase was a product of solidification from the melt or a product of a solid-state transformation, the microstructures of the welds were compared to those of samples cycled in a Gleeble 1500/20 Thermal-Mechanical Test System which was programmed to simulate the solid-state portion of the weld cooling rates (as predicted by a Rosenthal analysis). The microstructures were characterized by X-ray diffraction, optical and by scanning electron microscopy. The plate-like phase found in the weld microstructures was identified as TiB2 occurring upon rapid solidification of the melted weld metal.

Nano-scale microstructure of Fe3+-, OH−-bearing crystalline inclusions in experimentally oxidized olivine from a mantle nodule

2000 ◽  
Vol 64 (2) ◽  
pp. 319-335 ◽  
Author(s):  
N. R. Khisina ◽  
K. Langer ◽  
M. Andrut ◽  
A. V. Ukhanov ◽  
R. Wirth
Keyword(s):  
Solid State ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Uv Spectroscopy ◽  
Electron Diffraction Data ◽  
State Transformation ◽  
Solid State Transformation ◽  
Crystalline Inclusions ◽  
Precursor Phase ◽  
Ir And Uv Spectroscopy

AbstractAn olivine grain from peridotite nodule 9206 (Udachnaya kimberlite) was heated in air at 700°C for 9 h. It was investigated by EMPA, by IR and UV spectroscopy and by TEM. The TEM examination reveals hexagon-like inclusions up to several hundred nm in size with a core and rim structure. The AEM data show that the inclusions contain only Mg, Fe and Si as cations. The rims have almost the same composition as the olivine matrix whereas the cores are enriched in iron and depleted in Mg. Electron diffraction data, SAED and CBED, indicate that the rims are composed of a ‘secondary’ olivine while the cores are composed of coexisting feroxyhite FeOOH, bernalite Fe(OH)3 and β-cristobalite SiO2. The presence of nm-sized inclusions in minerals is expected to influence the interpretation of spectroscopic results if spectroscopy is carried out without knowledge of the microstructure.It is speculated that the complex microstructure of the inclusions is a result of a solid state transformation of a precursor phase, probably a hydrous magnesian silicate, during the experimental heating and oxidation.

The Morphology and Content of δ Ferrite in Non-Equilibrium Solidified 0Cr18Ni9 Austenitic Stainless Steel

2012 ◽  
Vol 535-537 ◽  
pp. 666-669
Author(s):  
Li Juan Shen ◽  
Yong Lin Ma ◽  
Shu Qing Xing
Keyword(s):  
Stainless Steel ◽  
Solid State ◽  
Austenitic Stainless Steel ◽  
Cooling Rate ◽  
State Transformation ◽  
Solid State Transformation ◽  
Circulating Water ◽  
Δ Ferrite ◽  
Non Equilibrium

The microsructural and content of δ ferrite in non-equilibrium solidified 0Cr18Ni9 austenitic stainless steel is studied by the coin with the circulating water. The solidified microstructure of the residual δ ferrite in different cooling rate is that during the course of solid-state transformation, austenite grows into ferrite gradually; corresponding to the increase of cooling rate, the microsructural of ferrite is skeletal, network, strip and block. The experiment demonstrates that the content of the residual δ ferrite is increase under the increase of the cooling rate.

scholarly journals Thermal Behavior, Crystal Structure, and Solid-State Transformation of Orthorhombic Mo–V Oxide under Nitrogen Flow or in Air

ACS Omega ◽  
2019 ◽  
Vol 4 (8) ◽  
pp. 13165-13171 ◽  
Author(s):  
Masahiro Sadakane ◽  
Katsunori Kodato ◽  
Nobuhiro Yasuda ◽  
Satoshi Ishikawa ◽  
Wataru Ueda
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Thermal Behavior ◽  
Nitrogen Flow ◽  
State Transformation ◽  
Solid State Transformation

Mechanistic Aspects of the Solid-State Transformation of Ammonium Cyanate to Urea at High Pressure

2007 ◽  
Vol 111 (15) ◽  
pp. 3960-3968 ◽  
Author(s):  
Raphael Méreau ◽  
Arnaud Desmedt ◽  
Kenneth D. M. Harris
Keyword(s):  
High Pressure ◽  
Solid State ◽  
State Transformation ◽  
Solid State Transformation

Solid-state Transformation of Achiral Crystals to a Chiral Crystal by Guest Release from Host–Guest Inclusion Crystals of Achiral Host Compound

2009 ◽  
Vol 38 (11) ◽  
pp. 1080-1081 ◽  
Author(s):  
Hironori Saito ◽  
Mitsuaki Suzuki ◽  
Hiroshi Miyamae ◽  
Naoto Hayashi ◽  
Keiji Kobayashi
Keyword(s):  
Solid State ◽  
State Transformation ◽  
Solid State Transformation ◽  
Host Compound

scholarly journals Maskelynite formation via solid-state transformation: Evidence of infrared and X-ray anisotropy

2015 ◽  
Vol 120 (3) ◽  
pp. 570-587 ◽  
Author(s):  
Steven J. Jaret ◽  
William R. Woerner ◽  
Brian L. Phillips ◽  
Lars Ehm ◽  
Hanna Nekvasil ◽  
...  
Keyword(s):  
Solid State ◽  
State Transformation ◽  
Solid State Transformation ◽  
X Ray
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