Determination of Thermal Diffusivity and Influence of Defect Structure in Alloys Based on the Fe-Al System

2013 ◽  
Vol 336 ◽  
pp. 129-134 ◽  
Author(s):  
E. Bernstock-Kopaczyńska ◽  
Magdalena Jabłońska
Keyword(s):  
High Temperature ◽  
Thermal Diffusivity ◽  
Defect Structure ◽  
Thermal Characteristics ◽  
Laser Flash ◽  
Structural Defects ◽  
Flash Method ◽  
Aluminium Content ◽  
Diffusivity Coefficient ◽  
Thermal Diffusivity Coefficient

Alloys of the Fe-Al system are interesting due to occurrence of long-range order and many thermal vacancies at high temperature, which lead to not only significant hardening, but also cause changes of physical properties. High temperature diffusion is conditioned by structural defects in solids, such as vacancies, foreign atoms and dislocations influencing thermal characteristics of a solid solution, among others the thermal diffusivity coefficient. Measurement of thermal diffusivity was performed at room temperature using the laser flash method. For characterization of the defect structure, positron annihilation lifetime spectroscopy was used. The data were presented for alloys with 28 and 38 at.% aluminium without chromium and containing 5 at. % Cr addition. The results showed that thermal diffusivity decreased with aluminium content and deviation from stoichiometry. In the studies, different structural defects in the alloys were observed.

scholarly journals Определение температуропроводности материалов методом нестационарного точечного нагрева

2020 ◽  
Vol 46 (1) ◽  
pp. 39
Author(s):  
Д.Ю. Головин ◽  
А.И. Тюрин ◽  
А.А. Самодуров ◽  
Ю.И. Головин
Keyword(s):  
Thermal Diffusivity ◽  
Laser Flash ◽  
Processing Technique ◽  
Flash Method ◽  
Diffusivity Coefficient ◽  
Thermal Camera ◽  
Absorbed Energy ◽  
Thermal Diffusivity Coefficient ◽  
Data Processing Technique

Express thermographic method for measuring thermal diffusivity of thin flat objects is described in the paper. It could be considered as modification or a branch of laser flash method, however it does not require sample cutting or two side access to the object. The method comprises step-like heating of the small area (~ 0.1 mm2) at the object surface by focused laser beam and continuous recording temperature distribution at the surface by thermal camera. Developed data processing technique does not require information about absolute temperatures or absorbed energy for determination of thermal diffusivity coefficient.

A high-temperature system based on the laser flash method to measure the thermal diffusivity of melts

1996 ◽  
Vol 17 (1) ◽  
pp. 253-261 ◽  
Author(s):  
Y. Maeda ◽  
H. Sagara ◽  
R. P. Tye ◽  
M. Masuda ◽  
H. Ohta ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Diffusivity ◽  
Laser Flash ◽  
Laser Flash Method ◽  
Flash Method ◽  
High Temperature System

Study of the Thermal Diffusivity Variation in Thin Duplex Steel Plates Welded by GTAW Process

2018 ◽  
Vol 930 ◽  
pp. 460-465
Author(s):  
Evandro Giuseppe Betini ◽  
Maurilio Pereira Gomes ◽  
Cristiano Stefano Mucsi ◽  
Temístocles de Souza Luz ◽  
Marcos Tadeu D'azeredo Orlando ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Welding Process ◽  
Laser Flash ◽  
Nitrogen Atmosphere ◽  
Steel Plates ◽  
Digital Data ◽  
Flash Method ◽  
Temperature Profiles ◽  
Butt Weld ◽  
Duplex Steel

This study describes the thermal diffusivity of thin duplex steel plates in the thickness direction measured using the laser-flash method after welding. The work reports the experimental efforts in recording temperature profiles of the grade UNS S32304 duplex steel during autogenous welding. The butt weld autogenous joints were carried out by the GTAW (gas tungsten arc welding) process with either argon or argon - 2% nitrogen atmospheres. The amount of nitrogen in the heat affected regions, after welding, was measured and correlated with the variation of the thermal diffusivity of the studied material. The temperature profiles were obtained using k-type thermocouples connected to a digital data acquisition system. Different thermal cycles and thermal diffusivity values were observed in the heat-affected zone (HAZ) for both samples. In the solidified zone (SZ) was observed similar increase of the thermal diffusivity values for the plates welded with pure argon and argon plus nitrogen atmosphere.

scholarly journals Measurement of Thermal Diffusivity of Steels at Elevated Temperature by a Laser Flash Method.

2002 ◽  
Vol 42 (5) ◽  
pp. 498-503 ◽  
Author(s):  
Tsuyoshi Nishi ◽  
Hiroyuki Shibata ◽  
Koichi Tsutsumi ◽  
Hiromichi Ohta ◽  
Yoshio Waseda
Keyword(s):  
Elevated Temperature ◽  
Thermal Diffusivity ◽  
Laser Flash ◽  
Laser Flash Method ◽  
Flash Method
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