MECHANICAL SPECTROSCOPY IN NITROGEN-IMPLANTED COPPER

The effects of nitrogen irradiation employing a plasma focus device on high purity polycrystalline copper are shown. It should be pointed ou t, that the effects of implantation process depend strongly of the pre vious thermal state of the sample. In fact a new damping peak at appro ximately 750 K appears in irradiated samples which were previously ann ealed during 1 hour at 1073 K,but neither new peak at 750 K was measur ed in samples previously annealed during 5 and 15 hours. However other new peak appears at 1000 K. Moreover in the first case non hysteresis effects between a run up and down in temperature were found in both d amping and modulus, but in the second one strong hysteresis effects ap peared.