Kumar Babu Surreddi

Al-based metal matrix composites reinforced with nanocrystalline Al-Ti-Ni particles

Al-based metal matrix composites containing different volume fractions of nanocrystalline Al70Ti20Ni10 reinforcing particles have been produced by powder metallurgy and the effect of the volume fraction of reinforcement on the mechanical properties of the composites has been studied. Room temperature compression tests reveal a considerable improvement of the mechanical properties as compared to pure Aluminum. The compressive strength increases from 155 MPa for pure Al to about 200 and 240 MPa for the samples with 20 and 40 vol.% of reinforcement, respectively, while retaining appreciable plastic deformation with a fracture strain ranging between 43 and 28 %.

Powder Metallurgy of High Strength Al90.4Gd4.4Ni4.3Co0.9 Gas‐atomized Powder

Al90.4Y4.4Ni4.3Co0.9 gas-atomized powder was hot pressed (HP) to produce highly dense bulk samples through combined devitrification and consolidation. The microstructure of the as-atomized powder is a mixture of amorphous phase with nanocrystalline fcc Al, whereas the consolidated samples consists of fcc Al and a series of intermetallic phases with or without residual amorphous phase depending on the hot pressing temperature (673 or 723 K). The HP samples exhibit a remarkable high strength of ~ 925 MPa (HP at 673 K) and ~ 820 MPa (HP at 723 K) combined with a plastic strain ranging between 14 and 30%. The reduction in strength for the sample HP at 723 K is linked to the complete crystallization of the powder with no residual amorphous phase.