Abstract
The free decay of flexural vibration in (Mn1−XCoX)Cu0.05 metalstable alloys was examined with a frequency of 210–310 Hz and the maximum strain of 1×10−5 as a function of temperature (125 K–370 K) and lattice structure. Only a small peak (SDC\simeq0.1%) near 240 K was found in the damping capacity of fcc alloys, while fct (both with c⁄a<1 and c⁄a>1) and fco alloys showed a high (SDC\simeq12%) but broad peak between 250 K and 280 K as well as a relatively large increase of damping capacity (SDC\simeq2% at 125 K) with decreasing temperature below 180 K.
Young’s modulus showed either a broad maximum or a minimum in this temperature range, depending on the alloy concentration. No anomalies were, however, observed in both the damping capacity and Young’s modulus at fcc/fct or fct/fco transition temperatures.
As compared with results of other γ-Mn alloys previously reported, these characteristics have been concluded to be essentially common to the γ-Mn alloys. Effects of cold rolling on these properties were further examined. But clarification of the detailed mechanisms of the damping process have not been aimed at.
