Effects of Be additions on microstructure, hardness and tensile properties of A380 aluminum alloy

The effects of beryllium (Be) on the microstructure, hardness and tensile properties of A380 aluminum alloy were investigated. The base and Be-containing A380 alloys were conventionally cast in a ductile iron mold. The microstructure evolution was investigated using SEM and optical microscope. The mechanical properties were assessed using tensile and hardness tests, finally the rapture surfaces of the used samples were studied to reveal the fracture mechanism in the presence of Be. The results revealed that the platelet β intermetallic phases were transformed into relatively harmless Chinese script Be-Fe phase and eutectic Si phases changed from flake-like particles into fine ones. The corresponding ultimate tensile strength (UTS) and elongation values increased from 270 MPa to 295 MPa and 3.7% to 4.7%, respectively. Additionally, the hardness of A380 alloy decreased continuously with increasing Be content. While the fracture surfaces of the unmodified A380 alloy tensile samples showed a clear brittle fracture nature, while finer dimple and fewer brittle cleavage surfaces were seen in the alloys with Be addition. Moreover, in the presence of Be, due to the refined phases, there has been a decrease in the values of hardness.