Analysis of microstructure evolution and deformation mechanism of nano-oxides Al2O3 dispersion strengthened copper alloy during compression at room temperature

Abstract

The refinement of grains to the size of ∼ 600 nm is observed in a nano-scaled Al2O3 dispersion-strengthened (ODS) Cu alloy under compression distortion. The plastic deformation mechanism of the ODS Cu alloy is studied by the observation and analysis of the evolution of grain size, dislocation density and distribution, and texture orientation during compression process. The deformation process can be divided into four stages, i.e., leaner deformation stage, plastic-strengthening transition stage, relative steady state stage and softening stage under ∼ 90 % compression, according to the stress-strain curves. The grains are found split into refined sub-grains by the net-like entangled dislocations due to the pinning effect of nano-scaled Al2O3 particles. The dislocation density of ODS Cu is found increasing within 30 % compression, and then remaining to a plateau under ∼ 30 %−60 % compression, but then under ∼ 60 %−80 % and ∼ 80 %−90 % compression, the dislocation density increases firstly and then decreases. The crystal orientation is transformed from the Goss texture {110}< 001 > to the inhomogeneous Shear texture {001}< 110 > during the compression process, due to the rotation of grains. This study provides a further understanding of the strengthening mechanism and a guidance for the design of ODS Cu alloys, which is significant for the prospective future structural applications.