Changes in the thermoelectric power of a Ni base superalloy induced by elastic and plastic strain

Induced changes in the thermoelectric power (TEP) of the Inconel 718 by elastic and plastic strain have been previously reported by López Cuéllar et al. [1]. Now, in this work, the TEP of a nickel-based superalloy Waspaloy with different heat treatments has been followed during stressing tests. In all cases plastic deformation has been attained. TEP measurement variations of ∼160 nV/°C have been attained for a certain heat treatment that produces the desirable γ′ phase, and low changes of TEP are observed for the treatment that does not produce γ′. Like for the Inconel 718, results indicate that TEP of the Wasploy is clearly affected by the elastic and plastic strain induced during tests. The previously proposed model to describe the change in TEP induced by the strain in specimens of Inconel 718 [1], is validated with the Waspaloy superalloy in this work. Thus, these results confirm that the TEP technique is a powerful tool to detect non-desirable states and levels of strain in alloys containing γ′ phase like the Waspaloy and Inconel superalloys.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Tensile tests promote changes in the thermoelectric power (TEP) of the Waspaloy. ► TEP of the γ′ phase is lineally affected by the elastic and plastic strains. ► A lineal model that correlates the elastic and plastic strains with the alloy's TEP is validated. ► TEP technique could be a tool of characterization that follows changes in the internal stress of superalloys.