摘要
采用喷射成形技术制备了高合金Vanadis4（V4）钢,应用金相、X射线衍射（XRD）、差示扫描量热分析（DSC）、透射电镜（TEM）等实验手段分析了该钢及其雾化粉末的微观组织.结果表明：喷射成形V4钢主要由马氏体、残余奥氏体及MC、M7C3组成;其晶粒大小与碳化物的形貌、大小及分布较传统工艺组织而言都得到了明显改善;高冷速条件下得到的雾化粉末尺寸大部分在80-100μm,其典型微观组织主要有枝晶、碎断的枝晶、枝晶及细小等轴晶的混合、等轴晶4种.喷射成形所具有的快速凝固特征是V4钢组织细化的主要原因,而在较高温度形成的大量VC对晶界的钉扎则是V4钢能得到细小晶粒的重要原因.
Vanadis4 （V4） steel was produced by spray forming. Optical metallography, X-ray diffraction pattern, DSC, and TEM were used to investigate the microstructures of the as sprayed V4 steel and the asatomized powders. It was found that the as-sprayed V4 steel is composed of martensite, retained austenite, MC and M7C3 carbides. The grain size, as well as the morphology, size, and distribution of the carbide are all greatly refined compared with those of the as-cast V4 steel. Four representative microstructures： dendrite, dendritic fragments, a mixture of dendrites, equiaxed grains and dendritic fragments, and equiaxed grains, are observed in the as-atomized powders, which mainly have the diameter of 80-100 μm. Rapid solidification inherent in spray forming is the key factor to cause the refinement of the V4 steel. In addition, a large number of VC carbides which are formed at relatively high temperature act as pinning points for the growth of the grains, that is another important factor for the maintenance of fine grains.
出处
《上海交通大学学报》
EI
CAS
CSCD
北大核心
2008年第5期773-777,共5页
Journal of Shanghai Jiaotong University
基金
上海宝钢集团“十五”重大项目(BG010102)
关键词
喷射成形
高合金钢
微观组织
spray forming
high alloy steel
microstructure
