【摘要】 超高碳（1.58%C）钢中的马氏体相变产物除了板条马氏体、片状马氏体外,还发现枣核状马氏体.HRTEM观察表明,枣核状马氏体的亚结构是高密度位错.位错密度高达10⁽130/cm²,未观察到孪晶.基于盘片状马氏体的理论分析表明,应变能与马氏体片的临界厚度（2t₀^*）无关,而与其临界直径（2r₀^*）有关;临界形核功（相变能垒）△G^*与马氏体晶核临界厚径比t₀^*/r₀^*的二次方成反比.t₀^*/r₀^*<1时,马氏体核呈圆片状;t₀^*/r₀^*>1时,晶核呈枣核状;当t₀^*/r₀^*（?）1时,晶核呈棒状.更多还原

【Abstract】 In the martensitic transformation of an ultrahigh carbon steel（UHCS）containing 1.58%C,a kind of jujube stone-like martensite has been observed in addition to lath and twinning martensites.The substructure of the jujube-stone-like martensite is high density dislocation with 10¹³/cm² and no twin has been found.Theoretical analysis based on a disc-like martensite grain shows that the strain energy is not relative to the critical thickness of the disc（2t₀^*）but relative to the critical diameter of the disc（2r₀^*）,and the critical nucleation energy△G^* is inversely related to the square of the critical aspect ratio,t₀^*/r₀^*,of martensitic grains.When t₀^*/r₀^*<1,martensitic nucleus is disc shape,t₀^*/r₀^*>1,the nucleus is jujube-stone-like and t₀^*/r₀^*（?）1,the nucleus is rod shape.更多还原