Pinning effect of reactive elements on structural stability and adhesive strength of environmental sulfur segregation on Al2O3/NiAl interface

摘要

It has been proved that the reactive elements improve the adhesion strength of the alpha-Al2O3/beta-NiAl interface significantly, and Hf may be the best choice among the common doping elements, including Hf, Zr, Dy, Y, La for the interface without impurity. However, when impurity sulfur has to be considered, it is found that La and Y enhance interface adhesion and mechanical stability strength of alpha-Al2O3/P-NiAl-S interface most obviously, rather than Hf. The fundamental mechanism of reactive elements tying up S in the interface and the selection of reactive elements have been studied via a combinational analysis of bond topology and electronic structure. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.