| Numéro |
J. Phys. Colloques
Volume 42, Numéro C5, Octobre 1981
ICIFUAS-7Seventh International Conference on Internal Friction and Ultrasonic Attenuation in Solids |
|
|---|---|---|
| Page(s) | C5-941 - C5-946 | |
| DOI | https://doi.org/10.1051/jphyscol:19815145 | |
Seventh International Conference on Internal Friction and Ultrasonic Attenuation in Solids
J. Phys. Colloques 42 (1981) C5-941-C5-946
DOI: 10.1051/jphyscol:19815145
HIGH DAMPING AND MODULUS CHARACTERISTICS IN A SUPERPLASTIC Zn-Al ALLOY
H. Kawabe1 et K. Kuwahara21 Department of Mechanical Engineering, Faculty of Engineering, The Hiroshima Institute of Technology, Itsukaichi, Hiroshima 738, Japan
2 Faculty of Engineering, Hiroshima University, Hiroshima 730, Japan
Abstract
Damping (δ) and modulus (f2) measurements in a Zn-Al alloy (27 mass % Al) at surface shear strain of 2~3x10-5 have been made using an evacuated torsion pendulum over the temperature(T) of 293~658K. In the superplastic condition, there is observed high δ of S.D.C.≈97% at 473~573K. In the non-superplastic condition, δ(=δe,) shows a maximum damping of S.D.C.≈90% at Ts (phase transformation T:550K), while f2(=f2e) indicates abrupt changes at Ts and positive T coefficients at T<≈Ts. Regarding δe, it is proposed that there exist 3 types of damping, i.e., a relaxation damping due to the viscous sliding at phase boundaries, a multiple relaxation type damping, and a damping correlated with the transformation-induced superplasticity. The asymmetric damped free oscillation behavior can be explained in terms of the mechanical model composed of S.L.S. and its mass.