THE INFLUENCE OF DYNAMIC SHEAR LOADING ON PLASTIC-DEFORMATION AND MICROSTRUCTURE OF TUNGSTEN SINGLE-CRYSTALS

The plastic deformation behaviour of high purity tungsten single crystals of [110] and [111] orientations has been investigated with a split Hopkinson bar under dynamic loading applied in simple shear at room temperature. The effects of strain rate, orientation and loading direction on the microstructure and mechanical behavior were studied. The characteristics of twinning and dislocation slip were observed by transmission electron microscopy on the (11BAR2), (110) and (2BAR11), (01BAR1) planes for crystal orientations of [110] and [111] respectively. The response of this material to dynamic shear loading is discussed in terms of possible dislocation and twinning mechanisms in both microscopic and macroscopic aspects.