Intermetallic growth kinetics and microstructure evolution in Al-Cu-Al metal-matrix composite processed by high pressure torsion

•Al-Cu in-situ composites were successfully fabricated using constrained HPT.•The main mechanism of Al2Cu growth in Al-Cu HPT sandwich composite is bulk diffusion.•The activation energy for the growth of Al2Cu intermetallic compounds is about 0.48 eV. Constrained high pressure torsion and subsequent annealing was used to fabricate Al-Cu-Al metal-matrix multilayered composite. The composite has a heterogeneous structure consisting of a plastic aluminum matrix and hard intermetallic inclusions with a gradient decrease of layer thickness from the center to periphery of the sample. Intermetallic growth kinetics was retrieved from precise X-ray phase analysis using a narrow parallel X-ray beam of increased intensity. It was found that the growth of Al2Cu phase at temperatures from 150 °C to 210 °C can be fitted by t1/2 time relation, indicating to the bulk diffusion-controlled growth kinetics. The growth activation energy of Al2Cu was calculated to be 0.48 eV.