The Effect of Niobium Addition on the Microstructure and Tensile Properties of Iron-Nickel Base A286 Superalloy

Soleimani Gilakjani, Reza; Razavi, Seyed Hossein; Seifollahi, Masoumeh

doi:10.22068/ijmse.18.1.7

Volume 18, Issue 1 (March 2021) IJMSE 2021, 18(1): 61-70 | Back to browse issues page

‎ 10.22068/ijmse.18.1.7

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Soleimani Gilakjani R, Razavi S H, Seifollahi M. The Effect of Niobium Addition on the Microstructure and Tensile Properties of Iron-Nickel Base A286 Superalloy. IJMSE 2021; 18 (1) :61-70
URL: http://ijmse.iust.ac.ir/article-1-1803-en.html

The Effect of Niobium Addition on the Microstructure and Tensile Properties of Iron-Nickel Base A286 Superalloy

Reza Soleimani Gilakjani

, Seyed Hossein Razavi

, Masoumeh Seifollahi

Abstract: (12410 Views)

Niobium addition is an appropriate approach for improvement of superalloy’s operation. The purpose of this study is twofold: (1) to investigate on the η and γ^/ phase precipitations along with (2) to identify the high-temperature tensile properties in A286 and Nb-A286, as a modified type. The heat treatment of both alloys was carried out in a two-stage aging procedure at 760°C for 16 h and 820°C for 2 to 30 hours, following characterized by optical and Scanning electron (SEM-EDS) microscopies, differential thermal analysis (DTA) and high temperature tensile tests. The results showed that niobium addition was increased the volume fraction of γ^/ phase, from 10.7% to 12%, decreased its size, from 94 to 71 nm, and rising the γ^/-dissolution temperature from 987°C to 1007°C. Moreover, the γ^/ to η phase transformation was sluggishly occurred in Nb-A286 due to more stable of γ^/ precipitations. Furthermore, the Nb-A286 alloy demonstrates higher mechanical properties than A286 one, approximately 100MPa improvement, which it was contributed to the much large volume fraction and finer size of more stabilized γ^/ phase.

Keywords: A286 superalloy, Niobium addition, η and γ/ phases, microstructure evaluation, hot-tensile properties