The use of PAP-2 aluminum powder to fabricate powder composites: Peculiarities of technology, structure, and physicomechanical properties of composites. Part 2. Study of composite properties and structure

Resumo

The possibility of reinforcing the Al/Al₂O₃ laminated cermet matrix with metal rapidly solidified alloy fibers (steel, titanium, and aluminum), as well as discrete duralumin chips, is shown. The maximal reinforcing effect was attained when using titanium and steel fibers with their content of 20 and 10 vol %, respectively, due to the implementation of several energy-intensive destruction mechanisms. Reinforced composites are characterized by the following properties: ρ = 2.30–2.85 g/cm³, σ_bend = 180–250 MPa, K_1c = 7.5–15 MPa m^1/2, and KCU = (18–35) × 10³ J/m². The Al/Al₂O₃–C_coke.residue has ρ = 2.21–2.23 g/cm³ at a very low sliding friction coefficient of 0.17 (the counterbody is a ball made of steel ShKh-15 under a load of 1 N). The oxide-adhesion bond type, which makes it possible to remove spent grains from the grinding work zone and implement the self-sharpening mode, is formed for the “Al/Al₂O₃–fused alumina grains” composite. The material that contains kaolin fibers is ultra-light-weight ceramic insulation (0.25–0.5 g/cm³), λ = 0.07–0.2 W/(m K) in the 20–1000°C range. The material including alumina spherulites combines rather high hardness (σ_bend = 10–50 MPa) and porosity (42–52%) and has increased thermal stability due to the rapid elimination of the temperature gradient on structural elements having a micrometer-size cross section.