一次淬火马氏体对Q&P钢组织和性能的影响

Effects of initial quenched martensite on microstructure and mechanical properties of quenching and partitioning steel

研究了一次淬火马氏体对低合金钢经淬火和配分（Quenching and Partitioning，Q＆P）工艺后微观组织和单轴拉伸性能的影响，用扫描电镜进行微观组织表征，用X射线法测量残留奥氏体量。试验结果表明，随着一次淬火马氏体比例的增加，二次淬火马氏体的尺寸和数量逐渐减少，残留奥氏体体积分数呈先增加后减少的趋势，一次淬火马氏体体积分数为40%时获得最大残留奥氏体体积分数为16.92%。一次淬火马氏体体积分数为30%～70%时试验钢获得了较高的塑性和强塑积，马氏体基体为钢提供了高强度，残留奥氏体在变形过程中的TRIP效应提高了钢的塑性。

Effects of initial martensite on the microstructure and mechanical properties of quenching and partitioning （Q＆P）low alloy steel were investigated. The microstructure characterization and austenite fraction measurement were car-ried out in scanning electron microscopy and X-rays diffraction. It was found that with increasing fraction of initial mar-tensite,the size and amount of fresh martensite decreased gradually,and the volume fraction of retained austenite in-creased firstly and then decreased,the maximum volume fraction of retained austenite of 16.92%was obtained when the initial martensite fraction was 40%. The higher ductility and the product of the tensile strength to total elongation could be obtained with the initial martensite fraction ranging from 30%-70%,the martensite matrix of steel guaranteed the high strength,and the TRIP effect of retained austenite during deformation improved the ductility of steel.