【摘要】 为了深入揭示淬火超高碳钢的马氏体亚结构及其产生的原因,通过对含碳量为1 4%(质量分数)的超高碳钢进行超细球化处理,获得了铁素体基体上分布超细碳化物的组织,并在此基础上进行了淬火处理.透射电子显微镜组织观测分析表明:奥氏体晶粒尺寸平均为2μm左右,淬火组织中存在大量板条马氏体,亚结构中含有大量位错与孪晶.通过计算证实,在马氏体亚结构形成过程中,随晶粒尺寸减小,孪晶切应力比滑移切应力升高得快,导致滑移成为变形的主要机制,位错大量增加.更多还原

【Abstract】 To reveal the sub-structure of martensite in a quenched ultra-high carbon steel, heat treatment was carried out to obtain ultra fine grains and carbides for a 1.4% C carbon steel, and the microstructure of ferrite with ultra fine carbides was obtained. Simultaneously the microstructure of the quenched steel was observed by transmission electron microscope. It is shown that the average grain size of austenite reaches 2 μm, a great deal of lath martensite exists in the quenched structure, and the sub-structure is composed of large quantity of dislocations and twins. The calculation confirms that the shear stress for twinning increases faster than that for slipping with the reduction of the grain size during the martensite transformation, which leads slipping to become the dominant deformation form, thus dislocation increases obviously.更多还原