Abstract
The growth kinetics of secondary recrystallized grains with specific orientations in the 90% hot rolled molybdenum sheets doped with CaO and MgO were investigated. Specific grains which are developed exclusively during secondary recrystallization in straight-and cross-rolled sheets have two kinds of orientaions with near {112}<111> and {335}<556>, and near {123}<121> and {126}<10, 81> respectively. The activation energies for the growth of secondary recrystallized grains with specific orientations were estimated to be 69-78 kcal/mol in the temperature range 1900-2200°C. The temperature dependence of the grain growth rate G was described by G=3.0×104 exp (-73000/RT) cm sec-1 for the {112}<111> orientation and G=5.4×103 exp (-70000/RT)cm sec-1 for the {123}<121> orientation. Moreover, the growth rates of secondary recrystallized grain are closely related to the crystallographic orientation relation between secondary and primary recrystallized grains, and the size of grains obtained for primary recrystallized sheets as results of rolling procedures.
