XLI. The internal friction of cold worked copper at low temperatures

Bordoni (1949 and 1954) has reported the existence at low temperatures of a large peak in the values of internal friction plotted against temperature for several cold worked metals, and we are making a more detailed survey of the position. Our work has so far been confined to experiments on 99·999% polycrystalline copper, arid it has been shown (Niblett and Wilks 1955) that the different types of results obtained by Bordoni for different metals can all be induced in copper by subjecting it to varying amounts of cold work. Although measurements are still in progress it seems worth while to give a preliminary report, particularly of those results which appear to be inconsistent with an explanation of the peaks, published recently by Mason (1955).