Effect of Hafnium on the Microstructure and Tensile Properties of 2A14 Aluminum Alloys

This study investigates how hafnium (Hf) content affects the evolution of precipitates, microstructure, and mechanical properties of 2A14 aluminum alloy. The addition of Hf increases the area fraction of α‐Al (Mn, Cr, Fe) Si dispersoids in the 2A14 alloy. When the Hf content is 0.10 wt%, the dispersoid volume fraction reaches a maximum. Under these conditions, the recrystallization proportion decreases from 24.04% in the Hf‐free alloy to 16.78%. At room temperature, the alloy with 0.10 Hf exhibits the maximum UTS of 495.68 MPa and YS of 410.35 MPa, representing an increase of 17.43 MPa in UTS and 33.1 MPa in YS compared with the Hf‐free alloy. Tensile tests conducted at 250 °C demonstrate that with an Hf content of 0.10 wt%, the ultimate tensile strength (UTS) and yield strength (YS) reach the highest, which are 271.03 and 263.27 MPa, respectively, and an elongation (EI) of 15.7%. Compared with the 2A14 aluminum alloy without Hf, the tensile and yield strengths are increased by 46.3 and 40.6 MPa, respectively. This is attributed to the θ′ and Q′ phases in the Hf‐containing 2A14 aluminum alloy not exhibiting noticeable coarsening.