Fabrication and characterisation of copper–alumina nanocomposites prepared by high-energy fast milling

Abstract

Two different methods are used to prepare Cu–20 vol-% Al2O3 nanocomposite powders via high-energy planetary fast milling. In the solid solution method, CuO powder was added to the Cu–Al solid solution powder, and the composite was fabricated by milling after 100 h. In the direct mixing method, Cu and Al2O3 powders were mechanically milled via high-energy planetary fast milling for 100 h. The transition electron micrographs (dark and white fields) revealed the presence of Al2O3 nanoparticles in crystalline Cu matrices for both methods. However, the density and bending strength of the nanocomposites produced via the solid solution method were higher than those of the samples produced via the direct mixing method.

Cold-Rolling Strain Hardening Effect on the Microstructure, Serration-Flow Behaviour and Dislocation Density of Friction Stir Welded AA5083

“…Notably, the Burgers vector (B) can be changed during rolling because of microstrain-induced disturbances, which are caused by the lattice parameter of Al deviating from the database of FCC (a = 0.4094 nm [55]). The Nelson-Riley function (Equation (3)) was utilised to obtain the lattice parameter of Al, as follows [53,56]:…”

Investigation of the Microstructure and Mechanical Properties of Copper-Graphite Composites Reinforced with Single-Crystal α-Al2O3 Fibres by Hot Isostatic Pressing

“…When a certain temperature was reached and when the composite materials met the corresponding dynamic conditions, dynamic recovery and recrystallization occurred. Meanwhile, the presence of reinforcements such as Al 2 O 3 particles, ZrO 2 particles and alumina whiskers influenced the pinning [50], thus inhibiting grain growth to a certain extent [51]. Some alloying elements such as La, exerted an effect on the refining grain.…”

Study of the AISI 52100 Steel Reuse Through the Powder Metallurgy Route Using High Energy Ball Milling

“…The submicrometer particles of alumina are considered incoherent precipitates that can inhibit the grain growth during the thermal treatment, when located in the grain boundaries 9,21,22 . In general, the authors [10][11][12][16][17][18][19] also observed that, increasing the milling times, the properties of the MMCs composed by a metallic matrix and alumina as reinforcement achieved better results of density, porosity, hardness and elastic modulus, due to the factors discussed during this work.…”

“…It happens due to the small percentage of alumina that was added to the powder. Other authors as [10][11][12]16,18,19 also investigated the effect that extending the milling times generates in the crystalline structure of MMCs composed by metallic powders and alumina. The studies attested that, by increasing the milling times, the amorphization phenomena continued to happens.…”

“…Thus, it is always indicated to control the granulometry of the powders before sintering 16 . Althought several authors in the literature studied the microstructural and mechanical properties of metal-matrix composites produced through the powder metallurgy route using high energy ball milling [10][11][12][16][17][18][19] , specific researches about the AISI 52100 steel with alumina additions were not found. Thus, this work aims to evaluate the microstructural and mechanical behaviour of this steel processed by these routes with different percentages of alumina additions.…”