类激光熔覆Stellite合金沉积层的组织及磨损性能

为了进一步提高316不锈钢的表面性能,采用类激光熔覆技术在316不锈钢表面制备了Stellite合金沉积层.利用扫描电子显微镜、能谱仪、X射线衍射仪、显微硬度计与销盘磨损试验机,研究了Stellite合金沉积层的微观组织、化学成分、显微硬度及摩擦磨损性能.结果表明,Stellite合金沉积层主要由γ-Co和M_(23)C_6相组成.沉积层组织依附于316不锈钢基体的界面呈外延生长,由界面至表面依次呈平面晶、柱状晶和胞状树枝晶形态,且越靠近表面组织越细小.Stellite合金沉积层的最高硬度可达650 HV.在摩擦磨损过程中摩擦系数随着法向载荷的增大而减小,磨损机制主要为黏着磨损、磨粒磨损和氧化磨损.

Microstructure and wear properties of Stellite alloy deposited layer prepared by like-laser cladding

In order to further improve the surface properties of 316 stainless steel, the Stellite alloy deposited layer was fabricated on the surface of 316 stainless steel by like-laser cladding technology. The microstructure, chemical composition, microhardness as well as the friction and wear properties of the deposited layer were investigated with scanning electron microscope(SEM), energy dispersive spectroscopy(EDS), X ray diffractometer(XRD), microhardness tester and pin-dish abrasion tester. The results show that the Stellite alloy deposited layer is mainly composed of γ-Co solid solution and M₂₃C₆ phase. The microstructure of the deposited layer exhibits the epitaxial growth attached to the interface of 316 stainless steel substrate. From the interface to the surface, the morphology of microstructure transforms from the plane crystal, columnar crystal to cellular dendrite crystal, respectively. In addition, at the position closer to the surface, the microstructure is much finer. The highest hardness of the Stellite alloy deposited layer is 650 HV. During the process of friction and wear, the friction coefficient decreases with increasing the normal loads. Furthermore, the wear mechanism is mainly adhesive wear, abrasive wear and oxidation wear.