Determination of dislocation damping in copper single crystals with stress pulse method

Dislocation damping in copper single crystals was determined by the stress pulse method. For this purpose very short stress pulses were used, maximum length 30 s, by which loading conditions of a metallic matrix in the frontal region of a propagating brittle crack were simulated. At loading by these very short stress waves, strain rates above 10⁴ s^–1 are achieved, however, the strain rate during loading is not constant. Therefore a technique was elaborated that enables to compare the measured results of mechanical characteristics with very short stress pulses ( const.) with results obtained on a device with a constant strain rate of the specimen. With the use of the dependence = ( ) the existence of damping mechanisms of a viscous character was proved and the damping coefficientB determined. These results agree with theoretical assumptions in 10,20] about the probable mechanical behaviour in the region of the propagating brittle crack.ikova 22, Brno, Czechoslovakia.