Here, we present an unexpectedly high ductility of the Be-Al alloy manufactured by investment casting. It was superior to most Be-Al based alloys reported so far, exhibiting high yield strength of 53~58 MPa, ultimate tensile strength of 111∼117 MPa, and high tensile strain of 14.1~18.8%. The many dislocations in the Be phase were primarily responsible for the exceptionally high mechanical characteristics. A high Schmid factor for pyramidal slip led to slip transfer between the Be grains and Al grains, which may have the effect of relieving stress concentration and delaying early fracture. The profuse activated pyramidal dislocations could render the unprecedented high tensile strain. The high strength was attributed to both the good interfacial strength and the hard Be phase's constraint, which made the soft Al phase strong like the hard Be phase. It was demonstrated that the strong texture microstructure design of the Be phase had a synergistic improvement in the strength-ductility balance, suggesting that this could be a useful tactic for enhancing the mechanical characteristics of Be-Al alloys.
Keywords: Investment casting，Be-Al alloy, Strong texture, High strength-ductility synergy, Pyramidal dislocations，slip transfer
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