熱間加工されたNi-30Fe合金の内部組織におよぼすせん断変形の影響

抄録

  Electron backscattered diffraction analysis has been used to investigate the effect of shear deformation on the microstructural evolution of a Ni-30Fe alloy during hot deformation. The alloy was compressed by 50% or 75% in thickness at a strain rate of 1/s in a single pass at 1023 K using a hot compression simulator. An explicit finite element analysis was carried out to evaluate the inhomogeneous strain distribution introduced in the specimens by hot compression simulator. As the equivalent strain increased, the fraction of high angle grain boundaries with misorientaions between 15° and 30° increased almost in the similar way regardless of the presence of shear strain. The fraction of high angle grain boundaries having misorientations in excess of 30° increased mainly at the expense of low angle grain boundaries with misorientations smaller than 15°. Such the expense occurred at much higher rate with shear strain than without shear strain. The compressive direction changed continuously in the areas with shear strain component during deformation, which was thought to accelerate the subdivision of austenite grain interiors with increased misorientations between subdivided local areas.