Damping characteristics of Ti 50 Ni 49.5 Fe 0.5 and Ti 50 Ni 40 Cu 10 ternary shape memory alloys
Journal
Metallurgical and Materials Transactions A
Journal Volume
26
Journal Issue
4
Pages
851-858
Date Issued
1995
Author(s)
Abstract
The damping characteristics of Ti50Ni49.5Fe0.5 and Ti50Ni40Cu10 ternary shape memory alloys (SMAs) have been systematically studied by resonant-bar testing and internal friction (IF) measurement. The damping capacities of the B19′ martensite and the B2 parent phase for these ternary alloys are higher than those for the Ti50Ni50 binary alloy. The lower yield stress and shear modulus of these ternary alloys are considered to be responsible for their higher damping capacity. For the same ternary alloy, the B19/B19′ martensite and R phase also have a higher damping capacity than does the B2 parent phase. In the forward transformations of B2 → R, R → 519′, and B2 → 519′ for Ti50Ni50 and Ti50Ni49.5Fe0.5 alloys, the damping capacity peaks appearing in the resonant-bar test are attributed to both stress-induced transformation and stress-induced twin accommodation. The lattice-softening phenomenon can promote the stress-induced transformation and enhance the damping capacity peaks. The Ti50Ni40Cu10 alloy had an unusually high plateau of damping capacity in the B19 martensite, which is considered to have arisen from the easy movement of twin boundaries of B19 martensite due to its inherently very low elastic modulus. The peaks appearing in the IF test for the Ti50Ni40Cu10 alloy are mainly attributed to the thermal-induced transformation due to T {superset of with not equal to} 0 during the test. © 1995 The Minerals, Metals & Material Society.
SDGs
Publisher
Springer-Verlag
Type
journal article