Multi-scaled polymer-based composite materials synthesized by mechanical alloying

Multi-scaled composite materials are of great importance, because they exhibit higher mechanical properties than those attained using conventional fillers or polymer blends. In this work, multi-scaled composite materials based on ultra-high-molecular weight polyethylene (UHMWPE), quasicrystals, polyimide and bronze are investigated for use in the moving parts of machines, gears, bearings, and sliding elements. The main object is to investigate the process of fabricating such composite materials, and to check if these materials are reproducible and reliable to an industrial extent. The specimens were prepared using a high-energy planetary mill. When milled with bronze, the quasicrystalline phase was dissolved into an intermetallic solid solution; milling with polymers showed to conserve the quasicrystalline phase, whereas the crystallization of UHMWPE was achieved during the milling process. Tribological study of consolidated samples showed an increase in the wear resistance for the bronze-containing composite materials. In comparison with pure UHMWPE, the polyimide-based specimen exhibited higher strength and hardness. This work has demonstrated the possibility of producing composite materials with acceptable and reliable properties using the mechanical alloying technology

Preparation and hydrogen storage properties of nanocrystalline TiFe synthesized by mechanical alloying

In this research, the mechanism of mechanical alloying (MA) synthesis of TiFe intermetallic compound (IMC) from individual components Ti and Fe has been studied. The partition coefficient of the apparent diffusion and the reaction rate constant during MA solid-state synthesis of the TiFe intermetallic compound in a planetary ball mill have been estimated. The results indicate that the apparent diffusion coefficient is close to 10–11 cm2/s that is approximately one order higher than the conventional high temperature diffusion coefficient. The reaction rate constant is close to 1.75·10−6. The relation between the structure and the hydrogen storage properties of MA synthesized IMC TiFe have been briefly discussed