Internal friction and dynamic Young modulus measurements have been performed in the temperature range 80–350 K on the Ti6Al4V alloy and a Ti6Al4V–SiCf composite reinforced by unidirectional SiC fibers (SCS-6). A vibrating reed apparatus operating at low strain amplitude (< 10− 5) in the frequency range 102–104 Hz was employed. Two anelastic relaxation peaks: P1, P2 have been observed in both materials. The peak temperatures at 1 kHz are respectively 120 K and 250 K. The fiber reinforced composite in the same temperature range shows a higher background damping and enhanced relaxation strength for the P1 peak. The activation energy and frequency factors evaluated from the peak temperature shift with frequency are respectively H1= 0.21±0.02 eV, H2= 0.50±0.03 eV and− 1 01= 1015 s− 1,− 1 02= 1012 s− 1. Both peaks position and relaxation strength depend on hydrogen content and the relative amount of defects in and phases.
Elsevier Science Limited
1 Jan 2009
Volume: 521 Pages: 340-342
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING