Tensile deformation-induced dislocation configurations at intermediate temperatures in a Ni-Fe-based superalloy for advanced ultra-supercritical coal-fired power plants

摘要

A low cost Ni-Fe-based superalloy due to its good mechanical properties and good workability has been evaluated as a promising candidate boiler material for advanced ultra-supercritical coal-fired power plants with temperature up to 700 degrees C. The major concerns with Ni-Fe-based alloys are the fundamental deformation mechanisms at intermediate temperatures. In this paper, great emphasis is placed on the dislocation configurations induced by tensile deformation in this low cost Ni-Fe-based superalloy. Two typical deformation-induced microstructure features, Orowan looping and precipitates shearing, are present during tensile deformation. Careful identification of dislocation-based deformation mechanisms by transmission electron microscopy was performed in tensile strained specimens at 20 degrees C, 500 degrees C, 650 degrees C, 700 degrees C and 750 degrees C in order to correlate the macroscopic behavior with the tension controlling mechanisms. (C) 2015 Elsevier B.V. All rights reserved.