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在试验室条件下,研究铝合金中初晶的存在状态,对材料使用性能和断裂过程的影响。结果表明,铸锭中的初晶以规则的条状和块状存在,与α-Al 的硬度差别很大。在加工变形过程中初晶阻碍α-Al 的正常流动,其自身破碎成块。在破碎的初晶与α-Al 之间形成微裂纹和不均匀的变形区。从而显著降低加工制品的塑性、疲劳寿命和断裂韧性。在受力状态下,初晶首先产生脆断,不但成为材料的断裂源,而且加速破断过程。
In the laboratory conditions, the study of the presence of primary crystals in the aluminum alloy, the use of materials and the fracture process. The results show that the primary crystals in the ingot are in the form of regular strips and lumps, which are different from the hardness of α-Al. In the process of deformation, the primary crystal obstructs the normal flow of α-Al and breaks itself into pieces. Micro-cracks and non-uniform deformation zones are formed between the crushed primary crystals and α-Al. Thus significantly reducing the plastic products, fatigue life and fracture toughness. Under the stress state, the primary crystal first produces brittle fracture, which not only becomes the source of fracture of the material, but also accelerates the breaking process.