Modelling ternary effects on antiphase boundary energy of Ni3Al

Vamsi, KV and Karthikeyan, S (2014) Modelling ternary effects on antiphase boundary energy of Ni3Al. In: 2nd European Symposium on Superalloys and their Applications, MAY 12-16, 2014, Giens, FRANCE.

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Abstract

The shearing of ordered gamma' precipitates by matrix dislocations results in the formation of antiphase boundaries (APB) in Ni-base superalloys. The APB energy is an important source of order-strengthening in disk and blade alloys where Ti and Ta substitute for Al in gamma'. While the importance of APB energy is well-acknowledged, the effect of alloying on APB energy is not fully understood. In the present study, the effect of Ti and Ta additions on the {111} and {010} APB energies was probed via electronic structure calculations. Results suggest that at low levels of Ti/Ta, APB energies on either plane increases with alloying. However, at higher Ti/Ta levels, the APB energies decrease with alloying. These trends understood by accounting for nearest neighbour violations about the APB and additionally, invoking the effect of precipitate composition on the energy penalty of the violations. We propose an Environment Dependent Nearest Neighbour Bond (EDNNB) model that predicts APB energies that are in close agreement to calculated values.

Item Type:	Conference Proceedings
Series.:	MATEC Web of Conferences
Publisher:	E D P SCIENCES
Additional Information:	Copy right for this article belongs to the E D P SCIENCES, 17 AVE DU HOGGAR PARC D ACTIVITES COUTABOEUF BP 112, F-91944 CEDEX A, FRANCE
Keywords:	PARTICLE HARDENING MECHANISMS; SUPERALLOY SINGLE-CRYSTALS; INITIO MOLECULAR-DYNAMICS; AB-INITIO; FAULT ENERGIES; SUPERLATTICE DISLOCATIONS; BASE ALLOYS; METALS; CREEP; SEMICONDUCTORS
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	29 Apr 2015 06:33
Last Modified:	29 Apr 2015 06:51
URI:	http://eprints.iisc.ac.in/id/eprint/51464

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