High-temperature deformation of dispersion-strengthened Cu–Zr–Ti–C alloys

The hot mechanical behaviour and microstructure of Cu–5 vol.% TiC, Cu–5 vol.% ZrO 2 and Cu–2.5 vol.% TiC–2.5 vol.% ZrO 2 alloys prepared by reaction milling were studied. After a test of 1 h annealing at 1173 K, the Cu–5 vol.% ZrO 2 alloy presented the lower softening resistance to annealing, while the other two ones kept their initial room-temperature hardness (about 2 GPa). Hot-compression tests at 773 and 1123 K, at initial true strain rates of 0.85 × 10 −3 and 0.85 × 10 −4 s −1 were performed. The Cu–2.5 vol.% TiC–2.5 vol.% ZrO 2 and the Cu–5 vol.% ZrO 2 alloys were the strongest and softest materials, respectively. Moreover, by electron microscopy, nanometric TiC and micrometric particles were detected in the Cu–5 vol.% TiC and Cu–5 vol.% ZrO 2 alloys, respectively. A possible explanation for the observed behaviour of these materials is proposed. In the compression tests, it was also found that strain rate has a low effect on flow stress, as it has been previously observed by various authors in dispersion-strengthened alloys deformed at high temperatures.