SUS304 ステンレス鋼における加工誘起マルテンサイト生成量と引張延性のひずみ速度依存性

抄録

We investigated martensitic (α') phase distribution in tensile-deformed SUS304 stainless steel by X-ray diffraction examination at the strain rate from 7.1×10^-4 /s to 9×10² /s. The elongation decreased with increasing the strain rate at the strain rate below 7.1×10^-1 /s and it was almost constant beyond the strain rate. On the other hand, the reduction of area was almost constant at the strain rate below 7.1×10^-1 /s and it gradually decreased with increasing the strain rate. The amount of α' phase (V_α') tended to decrease with increasing the strain rate, and it increased with decreasing the distance from a fractured face. The true strain is calculated from the cross-sectional reduction. The relationship between the true strain and V_α' is described using the Angel's equation, and the α' phase distribution is predicted from the true strain distribution. The V_α' of the total specimen (V_α',tot) and the V_α' around the fractured face (V_α',frac) are calculated from the α' phase distribution. The strain rate dependence of elongation correspond with the strain rate dependence of V_α',tot. The reduction of area tend to decrease with increasing strain rate above 7.1×10^-1 /s when the decrease in the V_α',frac was observed.