Mechanical strengthening and micro-mechanical modelling of newly fabricated 7068-aluminium/lightweight-high-entropy-alloy as aero-material

Abstract

On account of their lower densities and distinct properties, lightweight high entropy alloys (LHEA) are gaining prominence in the fabrication of particulate reinforced aluminum composites. In lieu of this, present report was conceived to achieve strength and ductility improvement in aluminum-7068 aerospace alloy by the inclusion of highly flexible Al30Li20Mg10Be20Ti10Cu10 LHEA (at 4, 10, and 16 wt%) as reinforcing phase. From the experimental outcome, the X-ray diffraction of the composites depicted BCC and FCC phases derived from LHEA addition. As the LHEA dosage increased, these phases became more prominent. Meanwhile, CuAl2, and MgBe13 intermetallic phases were equally identified in the composites. Based on the microstructure, the particles were sparsely dispersed at 4%, evenly dispersed at 10%, and exhibited both dispersed and clustered particles at 16%. The identified phases and the morphology played significant role in the mechanical characteristics of the fabricated composites ensuing strength improvement. Likewise, the plastic deformability of the composites was enhanced, resulting in a boost in strain hardening sensitivity and a decrease in necking susceptibility. The strengthening mechanism and the micro-models are herein discussed. According to the results, optimal efficacy was deduced at 10% LHEA.