Thermal and acoustic noises generated by austenite/martensite transformation in NiFeGaCo single crystals
Jerky character of austenite/martensite transformation has been investigated in NiFeGaCo shape memory single crystalline samples simultaneously by Differential Scanning Calorimeter, DSC, and by Acoustic-Emission, AE. Statistical analysis of the noise signals resulted in the same energy exponents, ε,...
Saved in:
Published in | Journal of alloys and compounds Vol. 658; pp. 29 - 35 |
---|---|
Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier B.V
15.02.2016
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Jerky character of austenite/martensite transformation has been investigated in NiFeGaCo shape memory single crystalline samples simultaneously by Differential Scanning Calorimeter, DSC, and by Acoustic-Emission, AE. Statistical analysis of the noise signals resulted in the same energy exponents, ε, about 1.7 ± 0.1 for heating, as well as 2.0 ± 0.1 for cooling, from both acoustic emission and thermal signals at low cooling rates (dT/dt = 0.1 K/min). The exponents of peak amplitudes of AE signals are α = 2.5 ± 0.1 and 2.9 ± 0.1 for heating and cooling, respectively. The obtained exponents fulfill the scaling rule (α−1)/(ε−1) = z with z = 2. Optical observation of the transformation confirmed that it takes place by single interface motion, i.e. the jerky character is the result of the stop-and-go type motion of this interface.
•Same critical exponents of energy distributions for thermal and acoustic noises.•The above noises were created by single interface motion.•Asymmetric acoustic noise: higher activity during heating than cooling.•The critical exponents of energy and amplitude reflect the above asymmetry. |
---|---|
Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0925-8388 1873-4669 |
DOI: | 10.1016/j.jallcom.2015.10.173 |