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研究了含C量1.6%超高碳钢不同淬火条件下马氏体的形貌及其亚结构。结果表明,超高碳钢淬火组织随奥氏体化温度变化而发生显著变化。奥氏体化温度较高时形成粗大孪晶马氏体;奥氏体化温度较低时淬火组织为位错亚结构的板条马氏体、枣核状马氏体和少量孪晶马氏体,以及未溶碳化物。高分辨电镜观察表明,三维形态像枣核状的马氏体的亚结构为高密度位错。这是由于奥氏体化时碳化物分解比铁素体向奥氏体转变慢;碳化物分解过程中在碳化物原位形成位错堆积;淬火时马氏体优先在位错堆积处形核,并以位错滑移机制长大、增厚,最终形成板条马氏体或枣核状马氏体。
The morphology and substructure of martensite under different quenching conditions for 1.6% super high carbon steel with C content were studied. The results show that the quenched microstructure of ultra-high carbon steel changes significantly with the austenitizing temperature. When the austenitizing temperature is high, coarse twins martensite is formed. When the austenitizing temperature is low, the quenched microstructure is dislocation subgrain lath martensite, jujube nucleated martensite and a small amount of twinned martensite As well as undissolved carbides. High-resolution electron microscopy showed that the three-dimensional morphology of jujube-like martensite substructure high density dislocation. This is due to austenitizing decomposition of carbides slower than ferrite to austenite; dislocations accumulate in the carbide in situ during carbide decomposition; martensite preferentially nucleates at dislocations at quenching , And grew up with the dislocation slip mechanism, thickening, and finally the formation of lath martensite or jujube nucleated martensite.