Microstructure indentation and corrosion properties of Al TiB2 AlCuFeMn Medium Entropy alloy reinforced composite

Abstract

Materials with high specific strength and modulus are crucial in the aircraft and automotive industries. Although aluminum alloys are versatile in this regard, a persistent need to develop materials with better specific strength, modulus, formability, corrosion resistance, and microstructural stability exists. Aluminum-based Metal Matrix Composites (MMCs) as a class of materials show significant promise in these aspects. Among different aluminum-based MMCs, Al-TiB2 in-situ composite exhibits potential in terms of good tensile strength, improved elastic modulus, fine particle size, and resistance to brittle layer formation at the matrix-particle interface. Moreover, the non-reactivity of covalently bonded TiB2 with aluminum matrix unlike in silicon carbide reinforced MMC improves the corrosion properties. However, in-situ TiB2 reinforcement is associated with brittle Al3Ti phase formation, and particle clustering with resultant loss of ductility, thereby, limiting the increase in the volume percentage of TiB2. newlineRecently, the incorporation of High/Medium Entropy (H/MEA) alloy particles like AlCoCrFeNi, AlMgLiCuZn, MoTaNaVW, CoNiFeAl0.4Ti0.6Cr0.5 as primary or secondary reinforcement in a soft matrix has shown significant promise. However, the H/MEA choice is critical as compatibility and complementarity with the matrix are essential. Firstly, the mechanical property of the H/MEA particle needs to supplement the softer matrix. Moreover, electrochemical similarity and a minimal interfacial reaction are desirable. newlineInvestigations on the corrosion characteristics of thermo-mechanically treated Al-5 wt.% TiB2 in-situ composite using friction stir processing reveal superior corrosion resistance compared to Al-B and Al-SiC composites. Corrosion, indentation, and oxidation experiments performed on AlCuFeMn alloy exhibited high strength, elastic modulus, and high-temperature resistance. Moreover, phase compositions and corresponding crystal structures in annealed AlCuFeMn alloy show good compatibility with aluminum metal.