Mechanisms of Grains Refining in Adiabatic Shear Band of Titanium Alloy

Abstract

Dynamic shearing high strain-rate experiments on three types of titanium alloy have been carried out by using a modified split Hopkinson bar. Microstructure and mechanism for grains refining in adiabatic shear band formed under the condition of high strain-rate were investigated by means of optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). It is shown that the mechanisms for grains refining in adiabatic shear band of titanium alloy mostly consist of three sorts. They are the mechanism of breakdown of elongated grains which due to action of dislocations,and the mechanism of rupture of twins and the mechanism of dynamic recrystallization, respectively. The mechanism of dynamic recrystallization is the universal one for grains refining in adiabatic shear band of titanium alloy. The formation of refining grains is usually a result of combined action of several sorts of mechanisms.