形变基带对低碳钢再结晶形核长大机制的影响

研究发现，在低碳钢强变形冷镦试样中存在分割晶粒的基块，用ＳＥＭ、ＷＤＳ以及ＴＥＭ分析探明了基块边缘的基带是由低碳无畸变的铁素体亚晶组成。再借助金相照片说明在随后的等温再结晶过程中，这种铁素体亚晶所组成的基带吞食其内部基块畸变区长大形成稳定的再结晶晶核。实验指出，低碳钢存在碳引起的再结晶晶粒长大的突破温度（ＴＢ）、其上、下的激活能差值等于碳在α－Ｆｅ中扩散激活能，且ＴＢ以上的再结晶激活能小于α－Ｆｅ

INFLUENCE OF DEFORMED MATRIX BAND ON RECRYSTALLIZATION NUCLEATION AND GROWTH OF LOW CARBON STEEL

Through a series of experiments,matrix grain seperting the grains is discovered inheavy - cooling deformed specimens of low carbon steel. By using SEM,WDS and TEM analysingmethods,it is probed that the edge of matrix band consists of the undeformed low carbon ferritesubgrains:During following constant temperature recrystallization, by the metallograph pictures,it is explained that the stable recrystallization nucleations are formed through the subgrain band consisting of undeformed low carbon ferrite devouring deformed matrix grain zone in the subgrains.The experiments indicate that there is a breaking temperature(T_B)of recrystallization grain growth,which is caused by the carbon in low carbon steel and the activation energy above T_B minus the activation energy below T_B equals the carbon diffusion activation energy in a-Fe,and the recrystallization activation energy above T_B is less than the diffusion activation energy of a-Fe grain boundary.These facts strongly support the preformed recrystallization nucleation theory.