工具钢表面激光熔覆Co基合金涂层的组织及性能

Microstructure and properties of cobalt-based alloy coating on tool steel surface prepared by laser cladding

通过送粉式激光熔覆在碳素工具钢(T10钢)表面制备了Co基合金熔覆涂层。利用扫描电子显微镜(SEM)和X射线衍射仪(XRD)分析其微观结构和相组成。结果表明:熔覆层中主要有γ-Co相以及其他相,包括Cr23C6、Co7W6和CrNi。从熔池与基体界面到熔覆层表面存在不同的凝固形态,依次为平面晶(在界面处)、胞状晶和树枝晶。微观组织较细的树枝晶强化了熔覆层,因而激光熔覆层的显微硬度增加,耐腐蚀性提高。

Co-based alloy coating was deposited on T10 tool steel by powder feeding laser cladding. Sections of such coatings were examined to reveal their microstructures and phases using scanning electron microscope （ SEM） and X-ray diffractometer （ XRD） . The results showed that the prime phase γ-Co and other phases, including Cr23C6,Co7W6 and CrNi existed in the coating. Some different solidification morphologies,such as planar （ at the interface） ,cellular and dendrite formed,varying from the interface to the surface. Fine microstructures of dendrite in dendritical regions strengthened the coating which caused the increases in microhardness and corrosion resistance in the laser cladded coating.