低合金钢中Mo溶质原子的拖曳效应

Solute drag-like effect of Mo in low alloy steels

对Mo在低合金钢和合金钢中的主要作用及对相变的影响进行了简要描述,重点分析了Fe-C-Mo合金中的Mo的偏聚行为及其对溶质原子拖曳效应的影响。Mo在晶界与界面存在明显的偏聚,Mo与C的相互作用形成了耦合的溶质原子拖曳效应。使Fe-C-Mo合金中的中温转变区域在TTT曲线中存在明显的港湾,在中温转变中存在不完全转变或者转变停滞现象。在港湾温度以下形成的铁素体(贝氏体)具有异常形态,被认为是由于棒状的亚结构激发形核形成的结果。Mo的碳化物析出后大大加速了退化铁素体的转变,强磁场可以加速Fe-C-Mo合金的中温转变和促进碳化物的析出。

The role and its effect on phase transformation of Mo was briefly reviewed in low alloy steels.The segregation of Mo and its effect on solute drag effect in Fe-C-Mo alloys was concentrated in this paper.Mo segregation occurs on austentite grain boundaries and austenite/ferrite interfaces.The coupled solute drag effect is believed to be resulted from the interaction of Mo and C.Owing to the solute drag effect,the deep bay is formed in the TTT diagram during intermediate temperature transformation in Fe-C-Mo alloys.Incomplete reaction or transformation stasis thus occurs during their intermediate temperature transformation.Peculiar morphology of its transformation product is observed below bay temperatures.It is found that it is composed of rod-like sub-units and formed by repeated sympathetic nucleation.The precipitation of molybdenum carbides greatly accelerates the transformation of degenerate ferrite.The transformation of Fe-C-Mo alloys at intermediate temperatures can be sped up by applying a high magnetic field.The molybdenum carbides are also promoted by applying a high magnetic field.