SiC表面合金化ZG45钢的组织观察

Microstructure Observation of SiC Surface-Alloyed ZG45 Cast Steel

以SiC粉末为主要原料制成涂料涂覆在EPS泡沫塑料模样的表面上。采用EPC真空消失模铸造方法浇注ZG45钢液,从而制备出SiC表面合金化ZG45钢基材料。采用光学显微镜、扫描电镜(SEM)和EDS观察和分析了材料的显微组织。结果表明:材料由表及里明显地由3个区域组成,即:表面合金化层、中间过渡层和内部基体层。在表面合金化层中,SiC颗粒已全部发生分解,组织由片状石墨+碳化物+富Si铁素体+珠光体组成;过渡层组织在靠近表面合金化层时全部由珠光体组成,而在靠近基体区域时组织由铁素体+珠光体组成,并且可以观察到部分晶粒中有少量的碳化物和富Si铁素体存在;基体由铁素体+珠光体组成。

The EPS patterns with surface coating that mainly consists of SiC powders were prepared. The patterns were then cast with ZG45 cast steel using EPC method, therefore the SiC alloyed surface layer was formed with ZG45 cast steel matrix materials. The microstructures of the material were observed and analyzed using optical microscope, SEM and EDS. The results show that the materials from surface to centre obviously consist of three different areas, i.e. the alloyed surface layer, the transitional layer and the matrix area in the centre. There is not any SiC particle in the alloyed surface layer and the microstructure of the layer consists of graphite flake, carbides, Si-rich ferrites and pearlites. A pearlite layer can be observed near the alloyed surface layer and with the increasing of distance from the surface, a mix of pearlite and ferrite layer occurs in the transitional layer. Moreover, there are a small amount of carbides and Si-rich ferrite in some matrix grains which is close to the matrix. The matrix consists of ferrite and pearlites.