Early Stage Reversed Crystal Growth of Zeolite A and Its Phase Transformation to Sodalite

2009 ◽  
Vol 131 (49) ◽  
pp. 17986-17992 ◽  
Author(s):  
Heather Greer ◽  
Paul S. Wheatley ◽  
Sharon E. Ashbrook ◽  
Russell E. Morris ◽  
Wuzong Zhou
Keyword(s):  
Phase Transformation ◽  
Crystal Growth ◽  
Early Stage ◽  
Zeolite A

From symmetry to entropy: Crystal entropy difference strongly affects early stage phase transformation

2019 ◽  
Vol 115 (26) ◽  
pp. 264103
Author(s):  
C. H. Hu ◽  
Y. C. Chen ◽  
P. J. Yu ◽  
K. Y. Fung ◽  
Y. C. Hsueh ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Early Stage

Microstructural Changes of Welded Zn-AI Alloy

1994 ◽  
Vol 367 ◽  
Author(s):  
Yao Hua Zhu
Keyword(s):  
Phase Transformation ◽  
Early Stage ◽  
Dendritic Structure ◽  
Metastable Phases ◽  
Grain Structure ◽  
Al Alloy ◽  
Cast State ◽  
Microstructural Changes ◽  
Fine Grain ◽  
Ageing Processes

AbstractExtruded eutectoid Zn-Al alloy was welded by a melt of the same eutectoid alloy. Two different microstructures were observed in the joint part and the bulk of the welded alloy. Typical dendritic structure of as cast Zn-Al alloy was observed in the joint part of the welded alloy. The bulk ofthe welded Zn-Al alloy appeared as fine grain structure. Two different metastable phases η'T decomposed from η's of chilled as cast state and η'E of extruded state were found to be unstable during early stage of ageing. A four phase transformation occurred after the decompositions of these two metastable phases of η'T. Microstructures of both joint part and bulk of the welded alloy were investigated parallely during ageing processes.

In situ Small-Angle and Wide-Angle X-ray Scattering Investigation on Nucleation and Crystal Growth of Nanosized Zeolite A

2007 ◽  
Vol 19 (8) ◽  
pp. 1906-1917 ◽  
Author(s):  
Wei Fan ◽  
Masaru Ogura ◽  
Gopinathan Sankar ◽  
Tatsuya Okubo
Keyword(s):  
Crystal Growth ◽  
Small Angle ◽  
Wide Angle ◽  
Zeolite A ◽  
X Ray ◽  
X Ray Scattering ◽  
Nanosized Zeolite ◽  
Ray Scattering

scholarly journals Macrodefects in Cubic Silicon Carbide Crystals

2010 ◽  
Vol 645-648 ◽  
pp. 375-378 ◽  
Author(s):  
Valdas Jokubavicius ◽  
Justinas Palisaitis ◽  
Remigijus Vasiliauskas ◽  
Rositza Yakimova ◽  
Mikael Syväjärvi
Keyword(s):  
Growth Rate ◽  
Silicon Carbide ◽  
Crystal Growth ◽  
High Temperature ◽  
Temperature Gradient ◽  
Early Stage ◽  
Growth Conditions ◽  
Temperature Ramp ◽  
Cubic Silicon Carbide ◽  
Sublimation Growth

Different sublimation growth conditions of 3C-SiC approaching a bulk process have been investigated with the focus on appearance of macrodefects. The growth rate of 3C-SiC crystals grown on 6H-SiC varied from 380 to 460 μm/h with the thickness of the crystals from 190 to 230 μm, respectively. The formation of macrodefects with void character was revealed at the early stage of 3C-SiC crystal growth. The highest concentration of macrodefects appears in the vicinity of the domain in samples grown under high temperature gradient and fastest temperature ramp up. The formation of macrodefects was related to carbon deficiency which appear due to high Si/C ratio which is used to enable formation of the 3C-SiC polytype.

Imaging of crystal growth-induced fine surface features in zeolite A by atomic force microscopy

2002 ◽  
Vol 54 (1-2) ◽  
pp. 79-88 ◽  
Author(s):  
Seyda Dumrul ◽  
Stephane Bazzana ◽  
Juliusz Warzywoda ◽  
Ronald R Biederman ◽  
Albert Sacco
Keyword(s):  
Atomic Force Microscopy ◽  
Crystal Growth ◽  
Zeolite A ◽  
Surface Features ◽  
Force Microscopy ◽  
Atomic Force ◽  
Fine Surface

Crystal Growth during the Solidification Process of Continuous Casting Slab

2011 ◽  
Vol 299-300 ◽  
pp. 282-286
Author(s):  
Shu Ying Chen ◽  
Guang Can Jin ◽  
Xu Dong Yue ◽  
Qing Chun Li ◽  
Guo Wei Chang
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Continuous Casting ◽  
Solid Phase ◽  
Early Stage ◽  
Primary Dendrite ◽  
Dendrite Spacing ◽  
Wave Crest ◽  
Simultaneous Increase ◽  
Primary Dendrite Spacing

Under the condition that the solid-liquid interface bends periodically in continuous casting, the expression of solid-phase growth rate adapting to continuous casting was set up, and then the growth rates were calculated. On this basis, the morphologic of crystal growth and the variation of primary dendrite spacing during continuous casting slabs were studied. The results show that the growth rate is the fastest when solid-phase moves to wave crest within a deformation periodicity, whereas the growth rate is the slowest when the crystal moves to wave hollow. The bigger the bulge size is, the greater the variation amplitude of the growth rate will become. The variation of the growth rate results in the S/L interface to develop towards a planar surface. Because the value is much smaller than the critical value of the transformation from cells to dendrites, and the crystals only grow in the fashion of dendrites. The primary dendrite spacing at wave crest is bigger than the primary dendrite spacing at wave hollow in early stage of columnar crystal growth, and the dendrite spacing at wave crest is basically equal with the dendrite spacing at wave hollow in the late stage of solidification, and they quickly simultaneous increase. Good correlation is obtained between the experimental results and the calculation results of the dendrite arm spacing.

Single Crystal Growth and its Microstructure in Co-Cr-Mo Alloys for Biomedical Applications

2012 ◽  
Vol 706-709 ◽  
pp. 561-565 ◽  
Author(s):  
Takayoshi Nakano ◽  
Keita Sasaki ◽  
Koji Hagihara ◽  
Takuya Ishimoto ◽  
Yusuke Fujii ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystals ◽  
High Strength ◽  
Martensitic Phase ◽  
Surface Shape ◽  
Martensitic Phase Transformation ◽  
Ε Phase ◽  
Ar Gas

Co-Cr-Mo based alloys have been widely employed as heat resistant materials and as biomaterials for implants because of their high strength and superior wear resistance. In general, the alloys exhibit a very complicated composition-dependent microstructure containing stacking faults and related mechanical properties. Thus, the essential properties must be clarified by using not only polycrystals but also single crystals. To our knowledge, single crystals and related properties have not been reported elsewhere. Thus, Co-Cr-Mo single crystals were grown and used to analyze the microstructure and the related properties. Single crystals with a composition Co-27 mass% Cr-6 mass% Mo alloy defined by ASTM F75 were grown by two single crystal apparatuses: the optical floating zone and the Bridgman methods. The single crystals with the smooth-surface shape were successfully obtained in the Bridgman method under an Ar gas atmosphere at a crystal growth rate of 5.0 or 2.5 mm/h. A portion of the crystals contain Al as Al2O3 precipitates from the crucible. Since the Al2O3 precipitate induces martensitic phase transformation from fcc (γ) phase to hcp (ε) phase, the single crystals were separated into two parts (a) containing Al2O3 precipitate and (b) in the absence of the clear precipitate. The microstructure was significantly altered by the martensitic phase transformation from the γ to ε phase induced by stress field or heating. In addition, variant formation of ε phase has a large influence on the mechanical functions of these Co-Cr-Mo alloys. Novel findings were preliminary obtained in the single crystals.

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