Affordable Access

Publisher Website

S′ and δ′ phase precipitation in SiCpreinforced Al1.2wt.%Cu1wt.%MgχLi alloys

Materials Science and Engineering A
Publication Date
DOI: 10.1016/0921-5093(95)10159-4
  • Precipitation
  • Microstructures
  • Transmission Electron Microscopy
  • Differential Scanning Calorimetry


Abstract The microstructures obtained in reinforced and unreinforced Al-1.2Cu-1Mg-χLi-0.1Zr (in wt.%) alloys during ageing at 170 °C were studied by transmission electron microscopy and differential scanning calorimetry. A small volume fraction of inhomogeneously distributed S′ (Al 2CuMg) is present in the monolithic 8090 alloy (Al-1.2Cu-1Mg-2.3Li-0.1Zr) aged up to 7 days. The addition of SiC particles reduces GPB-zone formation, but causes a denser and more homogeneous distribution of S′ which nucleates heterogeneously on dislocations. The addition of Li to an Al-Cu-Mg alloy reduces the Cu and/or Mg solubility, thus increasing the amount of S′ precipitates. The introduction of SiC particles enhances the formation during non-isothermal DSC heating of δ′ (Al 3Li) precipitates and their coarsening rate during isothermal ageing. A model is presented which links the density of I (Al 6Cu(Li, Mg) 3) and δ (AlLi) grain boundary precipitates to the width of the precipitate free zones around grain boundaries and around SiC particles.

There are no comments yet on this publication. Be the first to share your thoughts.