Effect of P Addition on the Texture Formation Attributable to Preferential Dynamic Grain Growth in Fe-3mass%Si during High-Temperature Uniaxial Compression Deformation

In order to clarify the effect of solutes on texture formation during high-temperature deformation of BCC solid solution alloys, the texture and microstructure formations in Fe-3.1 mass%Si (Fe-Si) and Fe-3.2mass%Si-0.12mass%P (Fe-Si-P) during high-temperature uniaxial compression deformation are studied. The analysis of true stress-true strain curves indicates that the stress exponents at 1173K for Fe-Si-P and Fe-Si are 3.4 and 3.8, respectively. This suggests the addition of phosphorous affects the motion of dislocations. Texture having high axis densities at < 001 > and < 111 > are formed both in Fe-Si and Fe-Si-P by the deformation up to a desired strain of 1.0. The volume fraction of < 001 > oriented region increases and that of < 111 > oriented region decreases with decreasing strain rate and increasing temperature. This tendency is more obvious in Fe-Si-P than Fe-Si. Microstructural observations by EBSD measurements reveal that the notable increase of the volume fraction of < 001 > oriented region is attributable to the preferential growth of < 001 > oriented grains. The growth of < 001 > oriented grains begins earlier and becomes more active in Fe-Si-P with increasing strain than in Fe-Si. The results suggest that the acceleration of the preferential growth of < 001 > in Fe-Si-P relates to the dislocation structure affected by the solute atmosphere.