【摘要】 通过对居里点以下在等温珠光体(P)相变过程中施加弱磁场的热力学及动力学研究,对珠光体相变中出现的再辉点、最高回升温度、相变不同阶段特征、最终转变量和相关的热动力学等进行了分析。结果表明:即使是弱磁场也可缩短相变孕育期,使相变时间相对延长,从而增加了珠光体转变量;珠光体在相变初期转变量较大,之后在较宽的等温时间内转变量逐渐增加;磁场对相变初期的"联发式生长"特征有促进作用;铸钢组织中的缩松缺陷会产生感应漏磁场,增加了形核位置及数量,起到了"相变反应焊合缺陷"的作用。更多还原

【Abstract】 The effects of magnetic filed on thermodynamics and kinetics of pearlite isothermal transformation were investigated.The shift of recalescence point,the corresponding temperature increase,features of different transformation stages,final pearlite transformation fraction(PTR),and related thermodynamics and kinetics were discussed.The results show that the incubation period of isothermal pearlite transformation is shortened,and therefore the transformation time and PTR in Fe-Si-Mn steel increase under magnetic field. A large amount of PTR forms during early isothermal pearlite transformation stage,then,PTR increases gradually during holding time.Applied magnetic filed can enhance the evoked growing-mode happening in the early stage of transformation.There may be a lot of induction leakage fields around the shrinkage porosities in the casting steel,which may increase the potential nucleation sites and have the effect of welding the shrinkage porosities through transformation.更多还原