Optimization of Strength and Plasticity in Layered Aluminum Composites Through High-Pressure Torsion Treatment

Abstract

The development of high-strength aluminum alloys with improved ductility is a crucial challenge for modern materials science, as high strength and ductility tend to be mutually exclusive properties. In this work, the composite material was fabricated using wire arc additives manufactured from AA1050 (commercially pure aluminum) and AA5056 (an Al–Mg system alloy) aluminum alloys. It was demonstrated that the addition of a lower-strength material into a high-strength matrix enhances the potential for deformation localization and results in an increased plasticity of the composite material. A further strengthening of the composite material was achieved through its deformation by a high-pressure torsion (HPT) technique. The mechanical properties of the material were thoroughly investigated before and after the HPT treatment. Static strength and plasticity were analyzed as a function of the deformation degree. Microstructural analysis was performed using scanning electron microscopy and X-ray diffraction. The optimal deformation route, providing the best combination of mechanical properties, was experimentally identified, along with key microstructural parameters of the formed composite with a bimodal grain structure. A deformation level corresponding to 36% of shear stress provides a yield stress of up to 570 MPa, an ultimate tensile strength of up to 664 MPa, and a relative elongation to failure of up to 7%. As a result of the deformation treatment, characteristic substructures with dimensions of ~250 nm and >1000 nm are formed, with a volume ratio of approximately 80/20.