Influence of Fe and Si impurities on the quench sensitivity of Al-Zn-Mg-Cu alloy

• Published in: Cai liao gong cheng = Journal of materials engineering no. 10; pp. 41 - 47
• Main Authors: Zhang, Xin-Ming, Yu, Cui-Juan, Liu, Sheng-Dan, Liu, Xing-Xing, Zhang, Pan, Wang, Ying-Ying
• Format: Journal Article
• Language: Chinese
• Published: 01.10.2013
• Subjects: Aluminum base alloys; Impurities; Intermetallic compounds; Iron; Quenching; Recrystallization; Scanning electron microscopy; Silicon; Supersaturation
• ISSN: 1001-4381
• DOI: 10.3969/j.issn.1001-4381.2013.10.007

The influence of Fe and Si impurities was investigated quenching by means of end-quenching tests, and microstructure analysis including optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results show that the addition of Fe and Si impurities leads to lower quench sensitivity, decreasing by 3.29% in maximum when characterize by hardness. With increasing the content of Fe and Si impurities, Al(7)Cu(2)Fe phase and Mg(2)Si phase content increased significantly, thus reducing the solutes concentration of Cu and Mg elements in the matrix, reducing the degree of supersaturation, which leads to lower quench sensitivity. Al(7)Cu(2)Fe phases and Mg(2)Si phases are favorable for recrystallization, but bad for the reducing quench sensitivity. This is attributed to the higher amount of the recrystallization grains and (sub)grain boundaries, which result in more heterogeneous precipitation of eta equilibrium phases during slow quenching. The influence of supersaturation