LAUSR

To surmount the longstanding puzzle of strength-ductility trade-off, efforts had been made to apply Mg - Ag microalloying on 5%TiB2/Al-4.5%Cu composites by in situ molten salt reaction and subsequent heat treatment. The obtained composites achieve an eye-catching tensile elongation (δ) of 6.1 ± 0.4%, while maintaining elevated ultimate tensile strength (UTS) of 497 ± 4 MPa and yield strength (YS) of 401 ± 3MPa. Comprehensive characterization demonstrated that the uniformly distributed TiB2 particles together with semi-coherent grain boundaries between the α-Al matrix and reinforcement phase (TiB2 particles, Ω-Al2Cu, σ-Al5Cu6Mg2) facilitated the dislocation motion integrally, which eliminated the stress concentrations, may be the main reason for amelioration in the strength-ductility trade-off of the composites when subject to rigorous multi-step heat treatment.