Grain Refinement and Corrosion Behavior of Solid-State Additive Manufacturing of AA6063 Al Alloy Composite

Abstract

The limited strength and corrosion resistance of the AA6063 Al alloy restrict its application in demanding engineering applications, necessitating the development of Al alloy composites. The present work describes the development of Al-alloy metal matrix composites (MMCs) through the addition of ZrO2 to the AA6063 alloy by friction stir rod additive manufacturing (FSRAM). It presents the comparative study of microstructure, tensile properties, microhardness, phases evolution, and corrosion behavior. Microstructural analysis revealed significant grain refinement in FSRAM-fabricated samples due to dynamic recrystallization, with additional refinement in the composite attributed to the pinning effect of uniformly dispersed ZrO2 particles. The AA6063/ZrO2 composite exhibited substantial improvements in yield strength and ultimate tensile strength, resulting from the combined effects of grain boundary and dispersion-strengthening mechanisms, though with a moderate reduction in ductility. Electrochemical corrosion studies in NaCl solution demonstrated that the composite possesses superior corrosion resistance, characterized by a higher corrosion potential and a lower corrosion rate, owing to the formation of stable and protective oxide layers. Overall, the results confirm that the FSRAM process is an effective route for producing high-strength and corrosion-resistant Al-based composites, highlighting the potential of AA6063/ZrO2 MMCs for advanced structural applications in automotive, aerospace, marine, and chemical industries. © The Minerals, Metals & Materials Society 2026.