The Effect of High-Pressure Torsion on the Structure and Mechanical Properties of the Al–Ca–Cu Alloy

To improve the strength-to-plasticity balance for Al–6% Ca–8% Cu (wt %), high-pressure torsion (HPT) and subsequent annealing are used. The structure of the cast alloy mainly consists of two [(Al) + AlCaCu] and [(Al) + (Al,Cu)4Ca + AlCaCu] eutectics. HPT with three revolutions leads to the formation mainly of the submicrocrystalline structure, refining eutectic particles, their more homogeneous distribution in the sample bulk, segregation of calcium from AlCuCa and (Al,Cu)4Ca particles, and supersaturation of (Al) solid solution with copper. Such a structure causes strengthening of the alloy by three and a half times but also leads to its embrittlement. Subsequent annealing at 400°С allows an adequate strength-to-plasticity balance to be reached.