Analysis of β´ (Cu₄Ti) Precipitation During Isothermal Aging of a Cu–4 wt%Ti Alloy

Abstract

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.