The stress distribution in torsionally deformed cylindrical polycrystalline copper samples was investigated. The strain in torsional deformation changes with distance from the torsional axis and thus the local extent of work hardening and consequently the local flow stress changes as well. The variation of the flow stress with radial position in the samples was measured by microhardness tests. ...

It is usually assumed that ‘fire hardening’ the tips of spears, as practised by hunter–gatherers and early Homo spp., makes them harder and better suited for hunting. This suggestion was tested by subjecting coppiced poles of hazel to a fire-hardening process and comparing their mechanical properties to those of naturally seasoned poles. A Shore D hardness test showed that fire treatment slight...