Phases and microstructures of high Zn-containing Al–Zn–Mg–Cu alloys

• Published in: Rare metals Vol. 35; no. 5; pp. 380 - 384
• Main Authors: Liu, Jun-Tao, Zhang, Yong-An, Li, Xi-Wu, Li, Zhi-Hui, Xiong, Bai-Qing, Zhang, Ji-Shan
• Format: Journal Article
• Language: English
• Published: Beijing Nonferrous Metals Society of China 01.05.2016; Springer Nature B.V
• Subjects: Alloys; Aluminum; ALUMINUM ALLOYS (50 TO 99 AL); Aluminum base alloys; Biomaterials; Chemistry and Materials Science; Energy; Homogenizing; INTERMETALLIC COMPOUNDS; Intermetallics; Materials Engineering; Materials Science; MATHEMATICAL ANALYSIS; Metallic Materials; MICROSTRUCTURES; Nanoscale Science and Technology; PHASES; Physical Chemistry; ZINC ALLOYS (50 TO 99 ZN); Zinc base alloys; 光学显微镜; 差示扫描量热法; 扫描电子显微镜; 显微组织; 热力学计算; 金属间化合物; 铝锌镁铜合金; 锌铝; Homogenization; High Zn; Al–Zn–Mg–Cu alloy; Microstructure
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-014-0222-6

Phases and microstructures of three high Zncontaining Al–Zn–Mg–Cu alloys were investigated by means of thermodynamic calculation method, optica microscopy（OM）, scanning electron microscopy（SEM）energy dispersive spectroscopy（EDS）, X-ray diffraction（XRD）, and differential scanning calorimetry（DSC） analysis. The results indicate that similar dendritic network morphologies are found in these three Al–Zn–Mg–Cu alloys. The as-cast 7056 aluminum alloy consists of aluminum solid solution, coarse Al/Mg（Cu, Zn, Al）2 eutectic phases, and fine intermetallic compounds g（MgZn2）. Both of as-cast 7095 and 7136 aluminum alloys involve a（Al）eutectic Al/Mg（Cu, Zn, Al）2, intermetallic g（MgZn2）, and h（Al2Cu）. During homogenization at 450 ℃, fine g（MgZn2） can dissolve into matrix absolutely. After homogenization at 450 ℃ for 24 h, Mg（Cu, Zn, Al）2 phase in 7136 alloy transforms into S（Al2Cu Mg） while no change is found in 7056 and 7095 alloys. The thermodynamic calculation can be used to predict the phases in high Zncontaining Al–Zn–Mg–Cu alloys.