Effects of under-aging treatment on microstructure and mechanical properties of squeeze-cast Al-Zn-Mg-Cu alloy

欠时效处理对挤压铸造Al-Zn-Mg-Cu合金显微组织及力学性能的影响（英文）

The effects of under-aging treatment on the microstructure and mechanical properties of Al-Zn-Mg-Cu alloy produced by squeeze casting were investigated using optical microscopy(OM),X-ray diffractometry(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and hardness and tensile testing.The results showed that most of secondary phases were dissolved intoα(Al)matrix while no significant grain growth happened under the condition of solution treatment at 470°C for 4 h.Due to the strengthening effect of GP zones,for alloys treated by under-aging process,the increase of aging time and aging temperature improved the ultimate tensile strength(UTS)and yield strength(YS),but decreased the elongation(δ)to some extent.By utilizing appropriate aging time and temperature,the best combination of strength and ductility could be obtained to fulfill the design requirements of automobile components.

采用光学显微镜、X射线衍射技术、扫描电镜、透视电镜以及硬度和拉伸试验研究欠时效处理对挤压铸造Al-Zn-Mg-Cu合金显微组织及力学性能的影响。结果表明,在470°C、4h的固溶条件下,绝大部分二次相溶解到α(Al)基体中,且枝晶未出现明显的长大。在欠时效工艺条件下,由于GP区的强化效应,随着时效时间和时效温度的增加,合金的抗拉强度和屈服强度增加,而伸长率下降。因此,可通过控制时效时间和时效温度获得具有较高强度和伸长率的合金,使汽车零部件性能达到设计要求。