1. School of Physics and Technology, Wuhan University, Wuhan 430072, Hubei, China 2. Dongfeng Commercial Vehicle Technology Center, Wuhan 430056, Hubei, China 3. School of Materials Science and Engineering,Huazhong University of Science and Technology, Wuhan 430074, Hubei, China 4. Department of Advanced Production Engineering, Engineering and Technology Institute Groningen, University of Groningen, Groningen 9747, The Netherlands
Plasma Transferred Arc Surface Alloying of Cr-Ni-Mo Powders on Compacted Graphite Iron
1. School of Physics and Technology, Wuhan University, Wuhan 430072, Hubei, China 2. Dongfeng Commercial Vehicle Technology Center, Wuhan 430056, Hubei, China 3. School of Materials Science and Engineering,Huazhong University of Science and Technology, Wuhan 430074, Hubei, China 4. Department of Advanced Production Engineering, Engineering and Technology Institute Groningen, University of Groningen, Groningen 9747, The Netherlands
ժҪ A Cr-Ni-Mo overlayer was deposited on the surface of compacted graphite iron (CGI) by the plasma transferred arc (PTA) alloying technique. The microstructure of Cr-Ni-Mo overlayer was characterized by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), and X-ray diffractometer (XRD). Results show that the cross-section consists of four regions: alloying zone (AZ), molten zone (MZ), heat affected zone (HAZ), and the substrate (SUB). The microstructure of AZ mainly consists of cellular ��-(Fe,Ni) solid solution, residual austenite and a network of eutectic Cr7C3 carbide while the MZ area has a typical feature of white cast iron (M3C-type cementite). The martensite/ledeburite double shells are observed in the HAZ. With decreasing the concentration of Cr-Ni-Mo alloys, the fracture mode changes from ductile in the AZ to brittle in the MZ. The maximum hardness of the AZ (450 HV0.2) is lower than that of the MZ (800 HV0.2). The eutectic M3C and M7C3 carbides increase the microhardness, while the austenite decreases that of the AZ.
Abstract��A Cr-Ni-Mo overlayer was deposited on the surface of compacted graphite iron (CGI) by the plasma transferred arc (PTA) alloying technique. The microstructure of Cr-Ni-Mo overlayer was characterized by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), and X-ray diffractometer (XRD). Results show that the cross-section consists of four regions: alloying zone (AZ), molten zone (MZ), heat affected zone (HAZ), and the substrate (SUB). The microstructure of AZ mainly consists of cellular ��-(Fe,Ni) solid solution, residual austenite and a network of eutectic Cr7C3 carbide while the MZ area has a typical feature of white cast iron (M3C-type cementite). The martensite/ledeburite double shells are observed in the HAZ. With decreasing the concentration of Cr-Ni-Mo alloys, the fracture mode changes from ductile in the AZ to brittle in the MZ. The maximum hardness of the AZ (450 HV0.2) is lower than that of the MZ (800 HV0.2). The eutectic M3C and M7C3 carbides increase the microhardness, while the austenite decreases that of the AZ.
2016, Vol. 23 
