Synthesis of nanodiamond reinforced silver matrix nanocomposites: Microstructure and mechanical properties

Abstract

Nanodiamond reinforced silver matrix nanocomposites with different nanodiamond content are produced from pure silver and nanodiamond powders by a combination of two severe plastic deformation methods, ball-milling and high-pressure torsion (HPT). The ball milling parameters are varied to improve the distribution of the nanodiamonds in the powder blends.An optimized processing route combining both processes has been developed to achieve a homogenous dispersion of small nanodiamond particles in a nanocrystalline silver matrix. The microstructure of these nanocomposites was characterized by scanning and transmission electron microscopy. The mechanical properties were characterized by microhardness measurements and tensile tests. An increasing amount of nanodiamonds (up to 5 wt% and 15 vol%, respectively) can raise the microhardness by up to 70 % and the tensile strength by up to 60 % of the values achieved in HPT deformed pure silver. The microhardness and tensile strength is about 5 times higher than microcrystalline pure silver.

Preparation and Characterization of the Cr-Nanodiamonds/MoN Coatings with Performant Mechanical Properties

“…Figure shows that in the Cr-DND layer of the combined Cr-DND/MoN coating there was a crease in surface carbon content. This result coincides well with reports that nan monds penetrate a metal plating film as particles trapped within the coating [45] a most cases form agglomerates [46]. It was proved that carbon is located on the surfa Ni-DND/ZrC coatings as nanodiamonds, forming agglomerates 0.7 to 3.5 µm in size Therefore, the increase in surface carbon content in the Cr-DND layer of th DND/MoN coating can be explained by the presence of carbon moving to the surfa the form of the nanodiamond agglomerates of the Cr-DND coating during the electro osition process of the coating.…”

Nanodiamond-Based Fibrous Composites: A Review of Fabrication Methods, Properties, and Applications

“…66 ND−metal composites can be formed through two steps: first ND is mixed with metal in a powder blend, and then consolidation is done. 67 Different consolidation methods are used to obtain a bulk material, e.g., sintering and spray deposition under various conditions. Table 1 shows some of the commonly used synthesis techniques of ND−metal composites and the ND types, amounts, and metal types.…”

“…It was found that ND composites with metals can improve their hardness, elastic modulus, compression properties, and wear and corrosion resistance. , Moreover, ND can be milled without causing structural damage, allowing for improved dispersion and crystal refinement in the metal matrix . ND–metal composites can be formed through two steps: first ND is mixed with metal in a powder blend, and then consolidation is done . Different consolidation methods are used to obtain a bulk material, e.g., sintering and spray deposition under various conditions.…”

Effect of Carbon in Severe Plastically Deformed Metals

“…Using silver as another matrix metal, nanocrystalline silver matrix composites with a homogeneous distribution (at the macro-and nanoscale) of different amounts of nanodiamonds have also been prepared by HPT [50] . In Figure 11, a TEM image of a silver matrix composite with 2 wt% nanodiamonds is shown, with the nanodiamonds indicated by the red lines.…”

“…Using silver as another matrix metal, NC silver matrix composites with a homogeneous distribution (at the macro‐ and nanoscale) of different amounts of nanodiamonds have also been prepared by HPT. [ 49 ] In Figure , a TEM image of a silver matrix composite with 2 wt% nanodiamonds is shown, with the nanodiamonds indicated by the red lines. In this case, the microhardness only decreases by 7% and 11% after annealing at 400 °C (0.54 T m ) and by 19% after annealing at even higher homologous temperatures (0.71 T m , 600 °C).…”