Effect of processing Technology on Microstructure and Properties of BT-20 Thick Alloy Plate
The effects of deformation temperature and rate on the microstructure and properties of BT-20 alloy thick plate were studied. Four microscopic structures and corresponding properties were obtained from different processing technologies. The results show that the lamellar structure blank become equiaxed structure through one or two continuous α+β deformation and above 70% total deformation rate. Near β deformation is the key to get two-state structure. Large β deformation or β deformation plus subsequent smaller α+β deformation can get basket-weave structure. After the blank goes in α+β small deformation, single smaller β deformation can get the flake Widmanstaten structure with original β grain boundary. The equiaxed and two-state structure have better plasticity because they have more primary α particle producing uniform strain, but the flake Widmanstaten structure which reserved original β grain boundary and short lath-shaped basket-weave structure have higher fracture toughness property due to different orientation per α beam field to make crack expansion path become zigzag.