Effects of Be additions on microstructure, hardness andtensile properties of A380 aluminum alloy
(1. School of Materials Science and Engineering, K.N. Toosi University of Technology, Tehran 19991143344, Iran;
2. Department of Metals, Institute of Science and High Technology and Environmental Sciences,
Graduate University of Advanced Technology, POBOX 76315-115, Kerman 7631133131, Iran;
3. School of Metallurgy and Materials Engineering, University of Tehran, Tehran 1749637181, Iran)
2. Department of Metals, Institute of Science and High Technology and Environmental Sciences,
Graduate University of Advanced Technology, POBOX 76315-115, Kerman 7631133131, Iran;
3. School of Metallurgy and Materials Engineering, University of Tehran, Tehran 1749637181, Iran)
Abstract: 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.
Key words: Be addition; A380 aluminum alloy; hardness; tensile properties; fractography