The Effect of Ag-Addition on Precipitation Sequence in Al-1.0mass%Mg2Si-Excess 0.4mass%Si Alloy
It is well known that Ag additional Al-1.0mass%Mg2Si-excess0.4mass%Si alloy (ex. Si-Ag alloy) has higher hardness and elongation than those of Al-1.0mass%Mg2Si-excess 0.4mass%Si alloy (ex. Si alloy). However, precipitation sequence of ex. Si-Ag alloy is not clear yet. In this work, precipitation sequence of ex. Si-Ag alloy has been investigated using high resolution transmission electron microscopy and X-ray energy dispersive spectroscopy. Precipitates were classified into several kinds by HRTEM images and SAED patterns, and relative frequencies of precipitates were also investigated. Its precipitation sequence was compared with that of ex. Si alloy. Type-A, Type-B and Type-C precipitates as special metastable phase in excess Si type Al-Mg-Si alloy, has been observed in ex. Si-Ag alloy, but β’ phase increased and Type-A and Type-B precipitate decreased in this study. Type-A precipitate was found at only grain boundary.
Young Won Chang, Nack J. Kim and Chong Soo Lee
K. Niwa et al., "The Effect of Ag-Addition on Precipitation Sequence in Al-1.0mass%Mg2Si-Excess 0.4mass%Si Alloy", Materials Science Forum, Vols. 561-565, pp. 239-242, 2007