【摘要】 采用光学显微镜和扫描电镜观察了低碳钢中晶内针状铁素体的二维金相组织形貌,运用计算机软件对铁素体的三维形貌进行了重构。试验发现钢中的MnS夹杂物对晶内铁素体形核有明显的促进作用,晶内有大量铁素体组织形成,晶内形核铁素体的三维形貌呈扁长片状,许多铁素体在空间中相互连接,并有相当数量的铁素体与夹杂物相连。由此推测铁素体的晶内形核有以下3种形核方式:在原有铁素体上激发生核;在夹杂物表面上直接生核;在已经存在的铁素体和夹杂物的交汇处形核。更多还原

【Abstract】 Two-dimensional metallographic microstructure of intragranular acicular ferrites in low carbon steel was studied with optical microscope and scanning electron microscope.The three-dimensional morphology of ferrites was reconstructed based on observed two-dimensional observations by the computer.It was found that the inclusions of MnS enhanced the nucleation of intragranular ferrites evidently.The three-dimensional morphology of ferrites presented prolate plate.A number of ferrites were connected to each other in space,and some of them associated with inclusions.Three possibilities are considered for the nucleation of ferrites:sympathetic nucleation on previous ferrite,nucleation of the ferrite directly on the inclusions′ interface and heterogeneous nucleation at the junction of a pre-existing ferrite crystal and inclusions.更多还原