2009 年 50 巻 1 号 p. 51-55
Severely drawn low-carbon ferritic steel wire was investigated to make clear the reason of its high tensile strength which is higher than that predicted from the hardness. The microstructure of a specimen subjected to a true strain of 6.6 consists of fine elongated grains and subgrains with high dislocation density. Neutron diffraction showed the existence of (hkl) intergranular residual stress, suggesting a composite strengthening mechanism. The reasons of higher tensile strength achieved by drawing in comparison with other severe deformation processes, like ECAP, ARB and HPT, are estimated to be texture, residual intergranular stress and high dislocation density.
