Damping Characteristics of Ti50Ni50−xCux (x = 0~30 at.%) Shape Memory Alloys at a Low Frequency

The damping characteristics of Ti50Ni50-xCux (x = 0~30 at.%) shape memory alloys (SMAs) at a low frequency have been studied using a dynamic mechanical analyzer. The magnitude of the tan delta value and the values of the storage modulus (E0) softening/hardening and the strain variation exhibited in...

Full description

Saved in:
Bibliographic Details
Published in:Materials 2014-06, Vol.7 (6), p.4574-4586
Main Authors: Chien, Chen, Wu, Shyi-Kaan, Chang, Shih-Hang
Format: Article
Language:English
Subjects:
Cooling
Damping
Low frequencies
Martensite
Martensitic transformations
Shape memory alloys
Softening
Strain
Temperature
Transformations
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The damping characteristics of Ti50Ni50-xCux (x = 0~30 at.%) shape memory alloys (SMAs) at a low frequency have been studied using a dynamic mechanical analyzer. The magnitude of the tan delta value and the values of the storage modulus (E0) softening/hardening and the strain variation exhibited in B2 reversible reaction B19 transformation are all higher than those in B2 reversible reaction B19' transformation. The larger E0 softening/hardening in B2 reversible reaction B19 can induce higher strain variation in this transformation. It is suggested that the greater mobility of the twin boundaries and the larger magnitude of the strain variation both cause the higher tan delta value exhibited in B2 reversible reaction B19 transformation, as compared with B2 reversible reaction B19' transformation. In comparison with that in B19' martensite, the E0 value in B19 martensite is low and not affected so greatly by changes in temperature. Relaxation peaks are observed in B19' martensite, but not in B19 martensite, because the latter has rare twinned variants. The activation energy of the relaxation peak is calculated and found to increase as the Cu-content increases in these SMAs.
ISSN:1996-1944
1996-1944
DOI:10.3390/ma7064574