Fig. 2: The flow strength of a high purity copper during high rate deformation and at yield upon quasi-static reloading.
From: Time limited self-organised criticality in the high rate deformation of face centred cubic metals
The specimens are initially deformed at the strain rate shown on the x-axis to a strain of 0.1. The solid red circles show strength measurements at the initial loading strain rate and 0.1 strain. The two-tone green measurements show the strength after reloading the interrupted specimens to yield at a fixed strain rate of 10−2 s−1 making the data set, to within some scaling factor, a measurement of the materials’ mechanical threshold8. A small number of measurements, shown by the two-tone diamond symbols, were performed without interrupt, showing the interrupting process did not affect the measurement of strength before interrupt. The transition in strength observed above 104 s−1 is still present in the specimens reloaded at 10−2 s−1, despite the removal of variations in instantaneous effects such as phonon drag. Panel b shows the same measurements on a linear strain rate axis. Error bars for reload measurements depict fractional errors matching the deviation in interruption strain from the target strain of 0.1. The error bars in high rate measurements display the greater of the effects from either dispersive oscillations or inertial effects. Discussion of inertial effects is presented in Supplementary Methods Section 1.
