近ZLA357 Al-Si合金的微观组织和力学性能

• 作 者: 赵荣达 伍复发 来忠红 朱景川 齐锦刚 张广安
• 机 构: 辽宁工业大学材料学与工程学院,哈尔滨工业大学,
• 出 处: 材料热处理学报
• 发表日期: 2014年S2期
• 关键词: 力学性能 微观组织 韧窝 人工时效 固溶处理 铸造缺陷 共晶 光学显微镜 透射电子显微镜 基体成分

利用光学显微镜、扫描电子显微镜、透射电子显微镜力学性能测试研究了近ZLA357Al-Si合金T5热处理后的微观组织和力学性能。结果表明:不加入元素铍的情况下,使合金中的铜含量提高到0.8%,其抗拉强度和硬度可以满足A357Al-Si合金的性能要求。但是,合金伸长率略低,断口结果表明塑性较差与存在铸造缺陷有关。合金的显微组织较为均匀,局域可以观察到缺陷。能谱分析表明韧窝对应的突起部位主要是球粒状的共晶Si相,而韧窝附近基体成分主要是α-Al和杂质Fe相。TEM结果表明,经过T5(固溶处理和长时人工时效)处理后,在合金基体上析出了弥散而细小的强化相,正是由于这些强化相的析出,保证合金的抗拉强度和硬度。

The microstructure and mechanical properties of T5 heat-treated near-ZLA357Al-Si alloy were investigated by optical microscope, scanning electron microscope and transmission electron microscopy. The results show that without adding elemental beryllium, the content of copper in the alloy is increased to 0.8%, and its tensile strength and hardness can meet the performance requirements of A357Al-Si alloy. However, the elongation of the alloy is slightly lower and fracture results show poor ductility associated with casting defects. Alloy microstructure is more uniform, local defects can be observed. The energy spectrum analysis shows that the dimples correspond to the spherulitic eutectic Si phase, while the matrix components near the dimples are mainly α-Al and Fe impurities. TEM results show that after T5 (solution treatment and long-term artificial aging) treatment, the precipitation of fine and dispersed phase in the alloy matrix is ​​precisely due to precipitation of these strengthening phase to ensure that the alloy tensile strength and hardness.