Fabrication and properties of low oxygen grade Al2O3
dispersion strengthened copper alloy①
dispersion strengthened copper alloy①
(School of Materials Science and Engineering, Central South University, Changsha 410083, China)
Abstract: The low oxygen grade Al2O3dispersion strengthened copper alloy without hydrogen-fired expansion was fabricated by the technique of vacuum hot press and hot extrusion. The mechanical and electrical properties measurements and microstructures observation on as-hot extruded, as-cold drawn and as-annealed Cu-Al2O3alloy were conducted. The results show that the addition of a suitable amount of boron in the alloy can lower the residual free oxygen content and then inhibit the hydrogen-fired expansion. The density,σb,σ0.2, hardness,δand electrical conductivity of the alloy reach 8.86 g/cm3(relative density of 99.6%), 340 MPa, 250 MPa, HB95, 24% and 93%(IACS) respectively after hot extruded with the extrusion ratio of 30∶1. Its properties have no change after annealed at 900℃for 1 h. Its strength increases after cold drawing, while its ductility and electrical conductivity drop gradually. Various properties of the cold drawn alloy can recover to those of as-extruded after annealed at 900℃for 1 h without the occurrence of recrystallization.
Key words: hydrogen-fired expansion; free oxygen; dispersion strengthen; Cu-Al2O3alloy