Enhanced tensile properties in a Cu-Al2O3 alloy via trace Ti addition

Highlights: • Ti enriches at the Cu/Al₂O₃ interfaces. • Ti dissolves into nanoscale Al₂O₃ particles. • Ti addition generates a fine dispersion of nanoscale Al₂O₃ particles. • Ti-doped sample shows enhanced mechanical properties. -- Abstract: Fine dispersion of nanoscale particles in particle-dispersion-strengthened metallic materials is crucial for good mechanical and physical properties of the materials. In this study, the introduction of a small amount of Ti (0.2 wt%) into a mechanically alloyed Cu-2.03 wt% Al₂O₃ alloy powder is observed to improve the dispersion of Al₂O₃ nanoparticles with an initial average size of ~50 nm and influence the Cu matrix microstructural features in bulk samples extruded from mechanically alloyed and annealed Cu-Al₂O₃ alloy powder compacts. Atom probe tomography (APT) analysis reveals that the Ti dopant simultaneously dissolves into the Al₂O₃ nanoparticles and segregates at the Cu/Al₂O₃ interfaces. Tensile results manifest that noticeably different tensile ductilities are derived for the extruded samples with ((9.3 ± 1.2)%) and without ((5.7 ± 0.5)%) Ti addition. This clear difference in ductility may be attributed to the relatively large ultrafine Al₂O₃ particles and the Ti-decorated Cu/Al₂O₃ interfaces. The experimental evidence is discussed here based on the effects of trace Ti alloying element on the stabilization of the Al₂O₃ nanoparticles, Cu matrix microstructural evolution and tensile properties.