Microstructure and wear characteristics of cobalt-based alloy deposited by plasma transferred arc weld surfacing

• Published in: Surface & coatings technology 2005-05, Vol.194 (2), p.238-243
• Main Authors: Hou, Q.Y., Gao, J.S., Zhou, F.
• Format: Article
• Language: English
• Subjects: Applied sciences; Cobalt-based alloy; Contact of materials. Friction. Wear; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Joining, thermal cutting: metallurgical aspects; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metallic coatings; Metals. Metallurgy; Microstructure; Other topics in materials science; Physics; Plasma transferred arc (PTA); Production techniques; Surface treatment; Wear; Welding
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2004.07.065

The microstructure and wear characteristics of Co–Cr–W series cobalt-based alloys deposited by plasma transferred arc (PTA) weld surfacing were investigated using optical micrograph, X-ray diffraction (XRD), scanning electron micrograph (SEM), transmission electron microscope (TEM) and dry sand abrasion tester (DSAT). Aging effects on the structure and wear resistance of the cobalt-based PTA layer were also studied. It was found that the as-welded coating consisted of a cobalt-based solid solution with face-centered cubic crystal structure and hexagonal (Cr,Fe) 7C 3. There were lots of stacking faults existing in the cobalt-based solid solution. After aging at 600 °C for 60 h, another carbide M 23C 6 with face-centered cubic crystal structure precipitated. Although the precipitation of carbide M 23C 6 can increase the hardness, the coarse of the microstructure and the change of the morphology led to the increase of the wear weight loss.