Ikeshita, SumihaStrodahs, AnsisSaghi, ZinebYamada, KazuhiroBurdet, PierreHata, SatoshiIkeda, Ken-IchiMidgley, Paul A.Kaneko, Kenji2016-04-012016-04-012016-04-01201610.1016/j.micron.2015.12.002https://infoscience.epfl.ch/handle/20.500.14299/125278WOS:000371369100001Variations of Vickers hardness were observed in Al-Mg-Mn alloy and Al-Mg-Mn-Sc-Zr alloy at different ageing times, ranging from a peak value of 81.2 HV at 54 ks down to 67.4 HV at 360 ks, below the initial hardness value, 71.8 HV at 0 ks for the case of Al-Mg-Mn-Sc-Zr alloy. Microstructures of samples at each ageing stage were examined carefully by transmission electron microscopes (TEMs) both in two-dimensions and three-dimensions. The presence of different types, densities, and sizes of particles were observed dispersed spherical Al3Sc1-xZrx and also block-shaped Al3Sc precipitates growing along <1 0 0>(Al) with facets {1 0 0} and {1 1 0} of the precipitates. TEM analysis both in two-dimensions and three-dimensions, performed on various samples, confirmed the direct correlation between the hardness and the density of Al3Sc. (C) 2015 Elsevier Ltd. All rights reserved.Precipitation hardeningTransmission electron microscopyEDX tomographyAl alloyAl3ScAl3Sc1-xZrxtext::journal::journal article::research article