Analysis of β´ (Cu₄Ti) precipitation during isothermal aging of a Cu–4 wt% Ti alloy

This work analyzed experimentally and numerically the growth kinetics of β^′ precipitation of a Cu–4 wt%Ti alloy after aging at 400, 500, and 600 °C for times from 0.0166 to 200 h. Results indicated that the precipitation process is almost controlled by nucleation and growth during aging at 400 °C, originating a slow growth kinetics of precipitation. In contrast, the coarsening of precipitates dominates the precipitation process during aging at 500 and 600 °C. The interfacial energy of interface between the α matrix phase and β^′ precipitates was determined to be about 0.1135, 0.0980, and 0.0725 Jm⁻² for aging at 400, 500, and 600 °C, respectively. These values suggest a coherent interface, which is in agreement with the flat faces of β^′ cuboid precipitates. Calculated Time–Temperature–Precipitation diagram for the β^′ precipitation indicated good agreement with experimental results. Precipitation hardening was higher for the slower growth kinetics of precipitation.