High temperature corrosion of laser additively manufactured CoNiCrAlY

A Co32Ni21Cr8Al0.5Y alloy (by mass percentage) has been additively manufactured by selective laser melting (SLM). The as-deposited alloy has a.. matrix dispersing Al-rich.. phase which is coarsened with time at high temperatures. The alloy grows a double-layered oxide scale consisting of outer (Co,Ni)(Cr,Al)(2)O-4 and inner Al2O3 during 1000 h isothermal oxidation in air at 900 and 1000 degrees C. The Al2O3 growth is dominated after a short term, particularly at the higher temperature. The growth rate of inner Al2O3 layer during cyclic oxidation with respect to isothermal oxidation at 1000 degrees C appears to be promoted, leading to extensive incorporation of Y-rich particles into the alumina-dominated scale. The CoNiCrAlY alloy mainly forms a major Al2O3 scale after 40 h during hot corrosion at 800 and 900. C under Na2SO4+NaCl mixture. The dependence of the microstructure of the oxide scales formed on the different corrosion conditions is fully discussed. (c) 2022 The Author(s). Published by Elsevier B.V. on behalf of Institute of Metal Research, Chinese Academy of Sciences. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)