オーステナイト系ステンレス鋼ならびにニッケル基合金における結晶方位回転の塑性ひずみ依存性

Abstract

Misorientation in austenitic stainless steels (Type316NG, Type304NG, KASUS304J1HTB) and nickel base alloy (Alloy690TT) was measured by Electron back scatter diffraction (EBSD). Kernel Average Misoirientation (KAM) values were calculated for each material and their calculated pitch dependency were consistent with the theory in the range of smaller plastic strain and the shorter calculated pitch. However, constant β, which is plastic strain and measured pitch dependency in KAM values for Alloy690TT was lower than those for austenitic stainless steels. For the misorientation gradient scatters in austenitic stainless steels, on the other hand, the gradient doesn't scatter in Alloy690TT. It suggests that continuous precipitates on grain boundary in Alloy690TT make grains uniformly when plastic strain was applied. Grain Orientation Spread (GOS) that is one of calculation methods of EBSD was also calculated and the plastic strain dependency was confirmed. Constant β derived from the dependency of GOS shows the approximately same values in austenitic stainless steels and Alloy690TT.