中碳铁基合金中马氏体的特征

Some Characteristics of Martensite in Medium Carbon Iron Alloy

应用电子及光学显微术对45钢及55钢中的马氏体形态、亚结构等特征进行了研究。结果表明,中碳铁基合金中马氏体的形貌是以板条状为主的混合马氏体形态,其典型的马氏体惯析面为{225}_y,随着奥氏体中碳浓度微区的波动,亦可发现{111}_y马氏体。{225}_y马氏体中的亚结构随马氏体的碳含量高低而变,有的以位错为主,有的则以孪晶为主。作者认为这种{225}_y马氏体是一种形态介于板条状和片状马氏体之间的一种特殊过渡形态马氏体。

This paper deals with the characteristics of the morphology and substructures of martensite in Fe-0.45％C and Fe-0.55％C alloys by means of optical and electron microscopy. It shows that the morphology of martensite in medium carbon steels is the mixed morphology of martensites which are mostly the lath martensites with a few acicular martensites. The typical habit plane of martensite in medium carbon steels is {225}_γ. The martensite with the {111}_γ or {259}_γ habit plane also can be found in the structure. The substructures of {225}_γ martensite are varied with the carbon content of martensite: some are mainly dislocations and some are mainly twinned crystals. We regard the {225}_γ martensite as a special kind of martensite in transition state.