Abstract
Abstract
Stacks, each consisting of 40 thin metallic layers, were compressed under loads of up to 5000 kg. Measurements of the electrical resistance of the stacks (i.e. for the 39 metal-to-metal contacts in series) revealed four distinct regions of deformation.
The extent of these regions was marked by sharp changes in the slope of the curves obtained when load was plotted against electrical conductance. The first change occured at a load of approximately 200 kg, irrespective of layer size, roughness, or hardness. Two further transitions occurred at pressures equal to 2·5 and 22·5 per cent approximately of the surface hardness. Above the upper transition point the bulk properties play a large part in the mechanism of surface deformation.
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