添加铍对A380铝合金显微组织、硬度和拉伸性能的影响

摘要

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 plateletβ 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.%研究铍对A380铝合金显微组织、硬度和拉伸性能的影响。采用传统的铁模铸造制备含铍和不含铍的A380合金。采用扫描电镜和光学显微镜研究合金的显微组织，采用拉伸试验和硬度测试研究合金的力学性能。研究样品的断口形貌，揭示添加铍对断裂机制的影响。结果表明，板状β中间相转变为相对无害的汉字状Be−Fe相，共晶Si相由片状相变为细小相。拉伸强度和伸长率分别从207 MPa和3.7%增加至295 MPa和4.7%。此外，随着铍含量的增加，A380合金的硬度减小。不含铍的A380合金拉伸样品表现为脆性断裂，而含铍合金具有细小韧窝和少量脆性断面。此外，由于添加铍细化了析出相，合金的硬度降低。