球墨铸铁激光熔覆新型Fe-lnconel625合金涂层的组织特征

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Abstract：Nodular Cast Iron （NCI）holds an important position in the industrial fields such as rail transportation and shipbuildingdue to its excelent mechanical properties.However，NCI is prone to crack formationand the generation of hard and britle white mouth structure during the welding repair process，which limits the selection of repair materials and the quality of repair.This study selected Fe-Inconel625 aloy powder and completed the surface repair of QT4Oo-18 nodular cast iron through laser cladding technology.The microstructure and phase composition of the cladding layer were characterized using optical microscopy （OM），scanning electron microscopy （SEM），and X-ray diffraction （XRD）.The results show that under theconditions of alaser power of 18ooW，a scanning speed of 200mm/min ，andapowder feedingrateof 14g/min ，theresultingcladding layer is free from defectssuch aspores andcracks，and the interfacial bonding strength exceeds 370MPa ，which ismore than 90% of the strength of the base material.In addition，the microhardnessof thecladding layer in the fine grain zone （FGZ） is about 680HV，while it decreases to about 34oHV in the coarse grain zone （CGZ），showing a good hardnessgradient， which provides a new method forimproving the efficiency and quality of repair.

Keywords： nodular cast iron; laser cladding;microstructure; microhardness

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铸铁是人类使用最早、应用最广泛的材料之一。（剩余5578字）