Effect of heat treatment on Ni-Al laser cladding layer on 20# steel surface

In order to analyze the influence of heat treatment on the laser cladding layer microstructure,ordering and properties of the intermetallic compounds,the theoretical analysis and experimental verification were carried out using X-ray diffraction experiment and hardness test methods.Through the above experiment,the X-ray diffraction curve of the coated metal,the phase analysis results of the X-ray diffraction of the coated metal and the hardness test data of laser cladding layer were got.The results of the X-ray diffraction experiments showed that the NiAl phase got ordering while the Ni3Al phase did not get ordering in the laser cladding process.The Ni3Al phase got ordering after 4h heat treatment at 1000°C,and the ordering of NiAl phase was retained during the process.The hardness test results showed that the average hardness of the laser cladding alloy layer was 440HV and the average hardness of the coating was 412HV after the heat treatment,with hardness decreased.Heat treatment is conducive to the ordering of the phase of the Ni-Al metal compound,makes laser cladding defects disappear and release stress.