| Abstract: | The effect of Al on microstructure evolution of a hypereutectoid steel(0.97%C) during deformation of undercooled austenite was investigated by hot uniaxial compression tests. The results indicated that the dynamic transformation during deformation of undercooled austenite included dynamic phase transformation, spheroidization of cementite and dynamic recrystallization of ferrite. The proeutectoid cementites were formed during equilibrium transformation, while the proeutectoid cementites were restrained by deformation of undercooled austenite and the interlamellar spacing of pearlite was reduced. With the addition of Al of about 1 wt%, the proeutectoid cementites were restrained during equilibrium transformation and dynamic phase transformation, the stability of undercooled austenite during deformation was increased, retarding the formation of pearlite and the interlamellar spacing of pearlite was decreased. During the spheroidization of cementite and dynamic recrystallization of ferrite, the coarsening of cementite was restrained and the size of cementite and ferrite was refined by the addition of Al of about 1 wt%. |
