Effects of Ti and Cr Additions in a Co�Ni�Al�Mo�Nb-Based Superalloy

Baler, N and Pandey, P and Singh, MP and Makineni, SK and Chattopadhyay, K (2020) Effects of Ti and Cr Additions in a Co�Ni�Al�Mo�Nb-Based Superalloy. In: Minerals, Metals and Materials Series, 12-16 September 2021, Seven Springs; United States, pp. 929-936.

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Abstract

In the present work, we show the feasibility of microstructural control by additions of Ti and Cr to a γ/γ� Co-30Ni�10Al�5Mo�2Nb superalloy. Solutioning at 1300 °C followed by aging at 900 °C leads to homogenous distribution of L12 ordered cuboidal γ� precipitates in face-centered-cubic (fcc) γ matrix. Compositional measurements show Al, Mo, and Nb partition to γ� that indicates the γ� can be described as (Co, Ni)3(Al, Mo, Nb). An addition of 2 at. Ti leads to increases in the γ� volume fraction from 56 to 70 and solvus temperature from 990 to 1030 °C. Ti strongly partitions to γ� with respect to γ matrix. Similarly, an addition of 10 at. Cr to the base alloy leads to a morphological transition of γ� precipitates from cuboidal to near spherical shape, indicating a direct influence on the γ/γ� lattice misfit. Unlike Ti, Cr partitions to γ matrix, and additionally, Cr influences Mo to partition into γ matrix. A combined addition of Ti and Cr leads to high γ� volume fraction ~76 and an increase in γ� solvus temperature to 1045 °C, while maintaining the spherical γ� morphology. These superalloys show 0.2 proof strength comparable to those of Co�Al�W-based superalloys. At 870 °C, 10 at. Cr and 2 at. Ti added alloys show higher specific 0.2 proof stress than Co�Al�W-based superalloys. The obtained results show the microstructural sensitivity of these Co-based superalloys toward their designing for better performance. © 2020, The Minerals, Metals & Materials Society.

Item Type:	Conference Paper
Publication:	Minerals, Metals and Materials Series
Publisher:	Springer Science and Business Media Deutschland GmbH
Additional Information:	cited By 0; Conference of 14th International Symposium on Superalloys, Superalloys 2021 ; Conference Date: 12 September 2021 Through 16 September 2021; Conference Code:244649
Keywords:	Chromium alloys; Cobalt alloys; Niobium alloys; Titanium alloys; Volume fraction, 0.2 Proof stress; Co-based superalloys; Face-centered cubic; Micro-structural; Microstructural control; Morphological transitions; Solvus temperature; Spherical shape, Superalloys
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	03 Dec 2020 11:16
Last Modified:	03 Dec 2020 11:16
URI:	http://eprints.iisc.ac.in/id/eprint/66783

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