On rolling workability of pure tungsten single crystals with (110) ) 7001{ and (001) 7110{ orientations at room temperature approximately 200 deg C. )]

Pure Tungsten single crystals with (110)[001] and (001)[110] orientations were grown by electron-beam zone-melting technique. And rolling deformation on their orientations was studied in the temperature range of room temperature to 200°C. The main experimental results obtained were as follows:(1) The (001)[110] specimen showed a considerable ductility on rolling above 100°C, but the (110)[001] specimen was fractured in a brittle manner even at 200°C.(2) An abnormal widening which was not observed in pure iron and 3%Si-Fe on rolling at room temperature was found in the (001)[110]specimen at 200°C.(3) In the (110)[001] specimen a crystal is rotated about the [\={1}10] axis normal to the rolling drection on rolling. The degree of the crystal rotation to the rolling reduction was found to be small at least up to 50% rolling reduction as compared with the result of 3%Si-Fe.The above phenomena are discussed in relation to the multiplication mechanism of dislocations at a relatively low temperature in tungsten crystals.