Effect of initial particle size on phase transformation temperature of surfactant capped Fe3O4 nanoparticles

2011 ◽  
Vol 109 (8) ◽  
pp. 084303 ◽  
Author(s):  
S. Ayyappan ◽  
G. Panneerselvam ◽  
M. P. Antony ◽  
N. V. Rama Rao ◽  
N. Thirumurugan ◽  
...  
Keyword(s):  
Particle Size ◽  
Phase Transformation ◽  
Fe3o4 Nanoparticles ◽  
Transformation Temperature ◽  
Phase Transformation Temperature ◽  
Initial Particle ◽  
Initial Particle Size

Thermodynamics of the tetragonal-to-monoclinic phase transformation in fine and nanocrystalline yttria-stabilized zirconia powders

2003 ◽  
Vol 18 (12) ◽  
pp. 2912-2921 ◽  
Author(s):  
Arun Suresh ◽  
Merrilea J. Mayo ◽  
Wallace D. Porter
Keyword(s):  
Particle Size ◽  
Phase Transformation ◽  
Transformation Temperature ◽  
Phase Transformation Temperature ◽  
Scanning Calorimetry ◽  
Fine Grained ◽  
Dopant Level ◽  
M Phase ◽  
Additional Strain ◽  
Enthalpy And Entropy Changes

The current study uses high-temperature differential scanning calorimetry to document the shift in phase-transformation temperature with particle size throughout a series of alloys in the zirconia–yttria system (0–1.5 mol% yttria). The tetragonal-to-monoclinic (T→M) phase-transformation temperature is seen to vary inversely with particle size. It is shown that a simple thermodynamic approach first proposed by Garvie predicts this inverse linear relationship. Subsequent determination of the key thermodynamic parameters therein (e.g., the surface and volume free energy, enthalpy, and entropy changes involved in the phase transformation) allows a complete predictive equation for the T→M phase transformation in the yttria–zirconia system to be developed as a function of particle size and yttria dopant level. The yttria–zirconia phase diagram is then redrawn with grain size as a third variable. It should be stressed that the current analysis is valid for particulate systems only; a parallel paper tackles the problem for fine-grained yttria–zirconia solids, where the approach is similar, but additional strain energy terms come into play.

scholarly journals Effect of initial particle size and various composition on the spark plasma sintering of binderless tungsten carbide

2021 ◽  
Vol 1758 (1) ◽  
pp. 012022
Author(s):  
E A Lantsev ◽  
N V Malekhonova ◽  
V N Chuvil`deev ◽  
A V Nokhrin ◽  
M S Boldin ◽  
...  
Keyword(s):  
Particle Size ◽  
Tungsten Carbide ◽  
Spark Plasma Sintering ◽  
Initial Particle ◽  
Initial Particle Size ◽  
Plasma Sintering ◽  
Spark Plasma

Capability of martensitic low transformation temperature welding consumables for increasing the fatigue strength of high strength steel joints

2020 ◽  
Vol 62 (9) ◽  
pp. 891-900
Author(s):  
Jonas Hensel ◽  
Arne Kromm ◽  
Thomas Nitschke-Pagel ◽  
Jonny Dixneit ◽  
Klaus Dilger
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Fatigue Strength ◽  
High Strength Steel ◽  
Transformation Temperature ◽  
Fatigue Cracks ◽  
High Strength ◽  
Filler Material ◽  
Phase Transformation Temperature ◽  
Filler Materials

Abstract The use of low transformation temperature (LTT) filler materials represents a smart approach for increasing the fatigue strength of welded high strength steel structures apart from the usual procedures of post weld treatment. The main mechanism is based on the effect of the low start temperature of martensite formation on the stress already present during welding. Thus, compressive residual stress formed due to constrained volume expansion in connection with phase transformation become highly effective. Furthermore, the weld metal has a high hardness that can delay the formation of fatigue cracks but also leads to low toughness. Fundamental investigations on the weldability of an LTT filler material are presented in this work, including the characterization of the weld microstructure, its hardness, phase transformation temperature and mechanical properties. Special attention was applied to avoid imperfections in order to ensure a high weld quality for subsequent fatigue testing. Fatigue tests were conducted on the welded joints of the base materials S355J2 and S960QL using conventional filler materials as a comparison to the LTT filler. Butt joints were used with a variation in the weld type (DY-weld and V-weld). In addition, a component-like specimen (longitudinal stiffener) was investigated where the LTT filler material was applied as an additional layer. The joints were characterized with respect to residual stress, its stability during cyclic loading and microstructure. The results show that the application of LTT consumables leads to a significant increase in fatigue strength when basic design guidelines are followed. This enables a benefit from the lightweight design potential of high-strength steel grades.

Phase Transformation Temperature of NiTi Alloy Sheet Examined by Lamb Wave

2011 ◽  
Vol 320 ◽  
pp. 359-362
Author(s):  
Kai Sheng Wang ◽  
Ru Hui He ◽  
Zhi Min Zhao
Keyword(s):  
Phase Transformation ◽  
Lamb Wave ◽  
Transformation Temperature ◽  
Lamb Waves ◽  
Niti Alloy ◽  
Alloy Sheet ◽  
Phase Transformation Temperature ◽  
Wave Method

In this study, the ultrasonic PZT transducers were used for exciting and receiving Lamb waves on NiTi alloy sheet. Lamb waves were measured when the temperature of the NiTi alloy changed. Analysis on frequency spectrums of the Lamb waves was also done. Some marked changes were observed in the dependence of the waveforms and the frequency spectrums of the Lamb waves versus temperature during phase transformation of NiTi alloy. The results show that phase transformation temperature of NiTi alloy sheet may be examined by Lamb wave method.

Factors Influencing Flocculation and Precipitation. Influence of Initial Particle Size

1941 ◽  
Vol 11 (3) ◽  
pp. 139-153 ◽  
Author(s):  
Ellington M. Beavers ◽  
James E. Magoffin ◽  
Frank K. Cameron
Keyword(s):  
Particle Size ◽  
Initial Particle ◽  
Initial Particle Size ◽  
Factors Influencing
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