Structure and microhardness of nanocrystalline composite alloys on the basis of Al and Ti

A nanotechnology for production of layered composite nanocrystalline Al-Si, Al(1Hf + 0.2Nb + 0.2Sn, wt %)-Si, Al(0.5Ce + 0.5Re + 0.1Zr, wt %)-Si, and Ti-Si alloys has been suggested. The structure of the nanocrystalline composites obtained has been studied by the methods of optical microscopy and scanning and transmission electron microscopy. Experimental data on the microhardness of layered composite nanocrystalline alloys on the basis of aluminum and titanium are given. The microhardness of the nanocrystalline two-layered Al-Si composite in comparison with submicrocrystalline aluminum increased by a factor of three. In the nanocrystalline two-layered Ti-Si composite (compacted from powders), the microhardness also increased by a factor of almost six in comparison with nanocrystalline titanium. In the nanocrystalline two-layered composite alloys of aluminum, the increase in microhardness in the case of the Al(Hf,Nb,Sn)-Si alloy was up to 45% as compared to the composite on the basis of the metallic foil and by a factor of two as compared to the powder-compact composite; and in the case of the Al(Ce, Re,Zr)-Si alloy, by a factor of 1.6 and 2.7, respectively. An increase in the number of layers in the composites had no significant effect on the level of microhardness.