Through the analysis of quantitative metallography of NbC reinforced Ni3 Si matrix composite coating prepared by laser cladding on surface of nickel-based superalloy GH864

a kind of method of digital image processing was put forward to analyze quantitatively the microstructure of laser cladding layer.Based on the Matlab software

the digital image processing methods suah as gray processing

smooth filtering

edge sharpening processing

threshold segmentation

edge detection and so on were adopted to deal with metallographic figure.NbC enhancement phase in the proportion of NbC/Ni3 Si matrix composite coating was calculated using ImageJ software under adding different concentration of[Nb+C]content conditions.The results show that the digital image processing method can realize processing and quantitative analysis of the metallographic image of microstructure of laser cladding layer.In microstructure of NbC/Ni3 Si matrix composite coating

NbC content reaches 3.193% with 8% [Nb+C]

and it reaches 5.350% with 15% [Nb+C]

and NbC is 5.857% with 20% [Nb+C].