In situ metallic porous structure formation due to ultra high heating and cooling rates during an electromagnetic pulse welding

2017 ◽  
Vol 128 ◽  
pp. 10-13 ◽  
Author(s):  
T. Sapanathan ◽  
R.N. Raoelison ◽  
N. Buiron ◽  
M. Rachik
Keyword(s):  
Porous Structure ◽  
Structure Formation ◽  
Electromagnetic Pulse ◽  
Cooling Rates ◽  
Heating And Cooling ◽  
High Heating ◽  
Pulse Welding

EBSD Coupled to SEM In Situ Annealing as a Tool to Identify Recrystallization Mechanisms - Application to Zr and Ta Alloys

2012 ◽  
Vol 715-716 ◽  
pp. 486-491
Author(s):  
Nathalie Bozzolo ◽  
S. Jacomet ◽  
M. Houillon ◽  
B. Gaudout ◽  
Roland E. Logé
Keyword(s):  
High Temperature ◽  
Short Duration ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Heat Treatments ◽  
Cooling Rates ◽  
Heating And Cooling ◽  
Orientation Mapping ◽  
High Heating

A heating stage as been developed to perform in-situ annealing in a SEM equipped with an EBSD system in order to study recrystallization mechanisms. High temperature treatments could then be performed inside the SEM, up to 1180°C and with high heating-and cooling-rates (~100°C.s-1). Samples were cooled down to room temperature to perform EBSD orientation mapping in between successive short-duration heat-treatments. Microstructure evolution snapshots obtained this way are presented in this paper to show recrystallization in Zircaloy4 and in pure tantalum.

Texture Evolution Under Fast Heating and Cooling Rates of Zirconium Alloys Studied In-Situ by Synchrotron X-Ray Diffraction

2020 ◽  
Author(s):  
Chi-Toan Nguyen ◽  
Alistair Garner ◽  
Javier Romero ◽  
Antoine Ambard ◽  
Michael Preuss ◽  
...  
Keyword(s):  
Texture Evolution ◽  
Zirconium Alloys ◽  
X Ray Diffraction ◽  
Fast Heating ◽  
Cooling Rates ◽  
X Ray ◽  
Heating And Cooling

scholarly journals Diabatic Heating and Cooling Rates Derived from In Situ Microphysics Measurements: A Case Study of a Wintertime U.K. Cold Front

2014 ◽  
Vol 142 (9) ◽  
pp. 3100-3125 ◽  
Author(s):  
C. Dearden ◽  
P. J. Connolly ◽  
G. Lloyd ◽  
J. Crosier ◽  
K. N. Bower ◽  
...  
Keyword(s):  
Diabatic Heating ◽  
Cold Front ◽  
Phase Changes ◽  
Ice Crystals ◽  
Model Framework ◽  
Cooling Rates ◽  
Model Calculations ◽  
Heating And Cooling

In situ measurements associated with the passage of a kata cold front over the United Kingdom on 29 November 2011 are used to initialize a Lagrangian parcel model for the purpose of calculating rates of diabatic heating and cooling associated with the phase changes of water within the cloud system. The parcel model calculations are performed with both bin-resolved and bulk treatments of microphysical processes. The in situ data from this case study reveal droplet number concentrations up to 100 cm−3, with planar ice crystals detected at cloud top, as well as columnar crystals produced by rime splinter ejection within the prefrontal warm sector. The results show that in terms of magnitude, the most significant rates of diabatic heating and cooling are produced by condensation growth of liquid water within the convective updrafts at the leading edge of the front. The peak temperature tendencies associated with condensation are typically found to be at least an order of magnitude larger than those associated with the ice phase, although the cooling effect from sublimation and melting occurs over a wide region. The parcel model framework is used in conjunction with the observations to assess the suitability of existing bulk microphysical treatments, of the kind used in operational weather forecast models. It is found that the assumption of spherical ice crystals (with diameters equal to the maximum dimension of those sampled), along with the use of negative exponential functions to describe ice particle size distributions, can lead to an overestimation of local diabatic heating and cooling rates by a factor of 2 or more.

A new DSC for high heating and cooling rates measurements

1988 ◽  
Vol 134 ◽  
pp. 389-394 ◽  
Author(s):  
Ken-Ichi Hirano ◽  
Tamio Ohshima ◽  
Hiroshi Okamoto ◽  
Ryozo Kato ◽  
Akikazu Maesono
Keyword(s):  
Cooling Rates ◽  
Heating And Cooling ◽  
High Heating

In-situ cryo-SEM investigation of porous structure formation of chitosan sponges

2016 ◽  
Vol 52 ◽  
pp. 41-45 ◽  
Author(s):  
Elena M. Ivan'kova ◽  
Irina P. Dobrovolskaya ◽  
Pavel V. Popryadukhin ◽  
Artem Kryukov ◽  
Vladimir E. Yudin ◽  
...  
Keyword(s):  
Porous Structure ◽  
Structure Formation ◽  
Sem Investigation

Cooling and Heating Characteristics of Ti-Ni Based Shape Memory Alloy Wire Actuators

2007 ◽  
Vol 124-126 ◽  
pp. 1649-1652 ◽  
Author(s):  
Jung Min Nam ◽  
Jae Hwa Lee ◽  
Yun Jung Lee ◽  
Tae Hyun Nam
Keyword(s):  
Cooling Rate ◽  
Heating Rate ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Heating Rates ◽  
Cooling Rates ◽  
Alloy Wire ◽  
Heating And Cooling ◽  
High Heating ◽  
Better Than

Ti-51Ni(at%) and Ti-40Ni-10Cu(at%) alloy wires with diameters of 0.3mm, 0.5mm and 0.7mm were prepared by drawing the alloy ingots fabricated by vacuum induction melting. Heating rates of the wires were investigated by measuring changes in temperatures of them while applying currents in the range of 1 A and 6 A to them and cooling rates were investigated by measuring changes in temperatures of them after cutting currents. Heating rate increased with increasing the amount of current, while cooling rate was kept constant. Both heating rate and cooling rate increased with decreasing diameter of wire. This suggested that high amount of current and small wire diameter were required for high heating and cooling rate. Comparing Ti-50Ni alloy wires with Ti-40Ni-10Cu alloy wires, heating rates of the latter was faster than that of the former, although cooling rates were almost same. This suggested that Ti-40Ni-10Cu alloy wires is better than Ti-50Ni alloy wires for the applications requiring high actuating rates.

scholarly journals Ultra-High Implant Activation Efficiency In GaN Using Novel High Temperature RTP System

1998 ◽  
Vol 512 ◽  
Author(s):  
X. A. Cao ◽  
C. R. Abernathy ◽  
R. K. Singh ◽  
S. J. Pearton ◽  
M. Fu ◽  
...  
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
High Temperature ◽  
Complete Loss ◽  
Surface Degradation ◽  
Cooling Rates ◽  
Heating And Cooling ◽  
Activation Efficiency ◽  
High Heating

ABSTRACTSi+ implant activation efficiencies above 90%, even at doses of 5×1015 cm−2, have been achieved in GaN by RTP at 1400–1500°C for 10 secs. The annealing system utilizes with MoSi2 heating elements capable of operation up to 1900 °C, producing high heating and cooling rates (up to 100 °C · s−1). Unencapsulated GaN show severe surface pitting at 1300 °C, and complete loss of the film by evaporation at 1400 °C. Dissociation of nitrogen from the surface is found to occur with an approximate activation energy of 3.8 eV for GaN (compared to 4.4 eV for AIN and 3.4 eV for InN). Encapsulation with either rf-magnetron reactively sputtered or MOMBE-grown AIN thin films provide protection against GaN surface degradation up to 1400 °C, where peak electron concentrations of ∼5×1020 cm-3 can be achieved in Si-implanted GaN. SIMS profiling showed little measurable redistribution of Si, suggesting Dsi ≤ 10-13 cm2 · s−1 at 1400 °C. The implant activation efficiency decreases at higher temperatures, which may result from SiGa to SiN site switching and resultant self-compensation.

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