Characterization of MCrAlY/nano-Al_2O_3 nanocomposite powder produced by high-energy mechanical milling as feedstock for high-velocity oxygen fuel spraying deposition

Al_2O_3 nanoparticles and MCrAlY/nano-Al_2O_3 nanocomposite powder(M=Ni,Co,or NiCo) were produced using high-energy ball milling. The MCrAlY/nano-Al_2O_3 coating was deposited by selecting an optimum nanocomposite powder as feedstock for high-velocity oxygen fuel thermal spraying. The morphological and microstructural examinations of the Al_2O_3 nanoparticles and the commercial MCrAlY and MCrAlY/nano-Al_2O_3 nanocomposite powders were investigated using X-ray diffraction analysis, field-emission scanning electron microscopy coupled with electron dispersed spectroscopy, and transmission electron microscopy. The structural investigations and Williamson–Hall results demonstrated that the ball-milled Al_2O_3 powder after 48 h has the smallest crystallite size and the highest amount of lattice strain among the as-received and ball-milled Al_2O_3 owing to its optimal nanocrystalline structure. In the case of developing MCrAlY/nano-Al_2O_3 nanocomposite powder, the particle size of the nanocomposite powders decreased with increasing mechanical-milling duration of the powder mixture.     

Fabrication of an r-Al2Ti intermetallic matrix composite reinforced with α-Al2O3 ceramic by discontinuous mechanical milling for thermite reaction

In this study, a powder mixture with an Al/TiO2 molar ratio of 10/3 was used to form an r-Al2Ti intermetallic matrix composite (IMC) reinforced withα-Al2O3 ceramic by a novel milling technique, called ...