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

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 degrees C to 210 degrees C can be fitted by t(1/2) time relation, indicating to the bulk diffusion-controlled growth kinetics. The growth activation energy of Al2Cu was calculated to be 0.48 eV. (C) 2019 Elsevier B.V. All rights reserved.