Fabrication of nano-TiCp reinforced Inconel 625 composite coatings by partial dissolution of micro-TiCp through laser cladding energy input control

Nano-particulate reinforced metal matrix composites (nPRMMCs) exhibit excellent comprehensive properties unmatched by conventional micro-particulate reinforced metal matrix composites (μPRMMCs). However, current techniques for fabricating nPRMMCs usually use nano-powders as raw materials, which are not preferred due to their agglomeration trend and harmful size. In this paper, we developed a technique to fabricate nano-TiCp reinforced Inconel 625 composite coatings by laser cladding of an Inconel 625 + 5 wt.% TiC powder mixture, particle size of the raw powders both in micrometer range. By controlling the specific energy input, the micro-TiCp partially dissolved into nanometer scale. The influence of specific energy input on particle size, morphology and the microstructure, phase constitution and mechanical properties of the composite coatings were investigated by scanning electron microscopy, X-ray diffraction, transmission electron microscopy and nano-indentation test. Nano-TiCp reinforced Inconel 625 composite coatings were achieved at the specific energy input of 25.3 kJ/g. The hardness and modulus of the nPRMMCs are 3.36 GPa and 190.91 GPa, increased by 10.33% and 12.39% respectively compared to laser cladded Inconel 625 substrate. The nPRMMCs show potential in applications such as the fabrication of turbine blades and engine components with improved performance.