Study On Thermal Constitutive And Crack Mechanism Of Ceramsite Materials By Laser Additive

This paper uses the laser cladding technology of laser material manufacturing technology on 45#steel plate for five kind of metal ceramic coatings,constructing the coating residual stress numerical model,and two kinds of the coating on the calculation of residual stress was carried out respectively,using metallographic microscope,scanning electron microscopy(SEM),energy spectrometer(EDS)to analyze crack of five kind metal ceramic coatings,interface bonding between metal and ceramic,and use the electrochemical workstation and hardness tester to test and analysis the corrosion resistance and hardness of two kinds of coating performance.The results are as follows:(1)A numerical model for the calculation of the residual stress of the metal ceramic coating was established,and calculating two kinds of different proportion of residual stress in cermet coating concretely;(2)Under the same laser processing parameters,the microstructure of the cladding layer after the solidification of metal ceramic powders with different ratio shows different microstructure,distribution and density distribution.As the composition of ratio of ceramic increase gradually,FJ-3 with FJ-17+WC30%of the quality of cross section morphology of cladding layer is different,when the ratio is 70%,the longitudinal perfoliate crack occurred in the coating,reducing the quality of coating;FJ-17 with cobalt coated tungsten cairbide powder of the quality of cross section morphology of cladding layer is gradually reduced,the probability of porosity and crack of coating increased gradually;With TiO2 and Al2O3 ceramic phase are added,the cracks of coatings began to appear after adding the amount of ceramic phase is 40%;For adding TiC ceramic phase,the appearance of coating is good on the whole.(3)The crack type of metal ceramic coating obtained by laser cladding technology mainly include shear crack,microscopic shrinkage crack,and three kinds of inclusion cracks,in metal ceramic coating are occurred,The main causes of cracks in the metal ceramic coating are residual stress in the coating that getting together to produce aggregation through the pores,and the crack is caused by three kinds of crack source,then bring out crack eventually.