TY - JOUR
T1 - Electron Microscopy Characterization of Ni-Cr-B-Si-C Laser Deposited Coatings
AU - Hemmati, I.
AU - Rao, J. C.
AU - Ocelik, V.
AU - De Hosson, J. Th. M.
PY - 2013/2
Y1 - 2013/2
N2 - During laser deposition of Ni-Cr-B-Si-C alloys with high amounts of Cr and B, various microstructures and phases can be generated from the same chemical composition that results in heterogeneous properties in the clad layer. In this study, the microstructure and phase constitution of a high-alloy Ni-Cr-B-Si-C coating deposited by laser cladding were analyzed by a combination of several microscopy characterization techniques including scanning electron microscopy in secondary and backscatter imaging modes, energy dispersive spectroscopy (EDS), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The combination of EDS and EBSD allowed unequivocal identification of micron-sized precipitates as polycrystalline orthorhombic CrB, single crystal tetragonal Cr5B3, and single crystal hexagonal Cr7C3. In addition, TEM characterization showed various equilibrium and metastable Ni-B, Ni-Si, and Ni-Si-B eutectic products in the alloy matrix. The findings of this study can be used to explain the phase formation reactions and to tune the microstructure of Ni-Cr-B-Si-C coatings to obtain the desired properties.
AB - During laser deposition of Ni-Cr-B-Si-C alloys with high amounts of Cr and B, various microstructures and phases can be generated from the same chemical composition that results in heterogeneous properties in the clad layer. In this study, the microstructure and phase constitution of a high-alloy Ni-Cr-B-Si-C coating deposited by laser cladding were analyzed by a combination of several microscopy characterization techniques including scanning electron microscopy in secondary and backscatter imaging modes, energy dispersive spectroscopy (EDS), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The combination of EDS and EBSD allowed unequivocal identification of micron-sized precipitates as polycrystalline orthorhombic CrB, single crystal tetragonal Cr5B3, and single crystal hexagonal Cr7C3. In addition, TEM characterization showed various equilibrium and metastable Ni-B, Ni-Si, and Ni-Si-B eutectic products in the alloy matrix. The findings of this study can be used to explain the phase formation reactions and to tune the microstructure of Ni-Cr-B-Si-C coatings to obtain the desired properties.
KW - Ni hardfacing alloys
KW - electron microscopy
KW - phase identification
KW - laser deposition
KW - coating
KW - phase formation
KW - ORIENTATION IMAGING MICROSCOPY
KW - AUSTENITIC STAINLESS-STEEL
KW - BACKSCATTER DIFFRACTION
KW - HARDFACING ALLOYS
KW - PHASE DIFFERENTIATION
KW - INTERMETALLIC PHASES
KW - MICROSTRUCTURE
KW - CLAD
KW - IDENTIFICATION
KW - EBSD
U2 - 10.1017/S1431927612013839
DO - 10.1017/S1431927612013839
M3 - Article
VL - 19
SP - 120
EP - 131
JO - Microscopy and Microanalysis
JF - Microscopy and Microanalysis
SN - 1431-9276
IS - 1
ER -