結晶組織依存性変形誘起マルテンサイト変態のモデル化と評価

抄録

A crystalline orientation dependent transformation model has been developed and finite element simulations clarify the effects of the crystalline orientation on the deformation and transformation behavior of TRIP steels. The results revealed that the deformation and transformation behavior of single crystal substantially depend on the maximum value of the Schmid factors of all slip systems. Decreasing the value of the Schmid factors raises the yield stress and drives the transformation in the early stage of deformation. In the later stage of deformation, the transformation behavior depends on the rotation of crystalline orientation due to the non-uniform deformation in the crystal grain. Meanwhile, the deformation and transformation behaviors of polycrystalline is strongly affected by not only individual crystalline orientation but also the situation of the distribution of crystalline orientation. The increase in the deviation of the distribution of the crystalline orientation causes significant non-uniform deformation due to misalignment of crystalline orientation with respect to the neighboring crystals, which promotes the transformation. Therefore, the transformation and deformation behavior may not be reproduced by the simple superposition of those of single crystals.