2009 年 50 巻 9 号 p. 2277-2284
In this study, hot forging process of Co-Ni-Cr-Mo superalloy was carried out at temperatures ranging from 950 to 1200°C and strain rates ranging from 0.01 to 30 s−1. In order to obtain an optimum forging condition, various processing maps were constructed, such as a power efficiency map and an instability map, at different strain levels on the basis of a dynamic material model. At a strain of 0.5, temperatures 1050–1200°C and strain rates of 10–30 s−1, dynamic recrystallization was observed with power efficiency values ranging from 35 to 44%. Flow localization due to dynamic strain aging and/or deformation twinning at temperatures 950–1000°C and at low strain rates were observed to be in good agreement with those observed in the instability map.
