Effect of Shear Deformation on Microstructural Evolution of Ni-30Fe Alloy during Hot Deformation

摘要

Electron backscattered diffraction anal) sis has been used to investigate the effect of shear deformation on the microstructural evolution of a Ni-30Fe alloy during hot deformation The alloj was compressed 50 percent or 75 percent in thickness at a strain rate of 1/s in a single pass at 1023K using a hot compression simulator An explicit finite element analysis was earned 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 deg and 30 deg 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 deg increased mainly at the expense of low angle grain boundaries with misorientations smaller than 15 deg. 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.