MATERIALS TRANSACTIONS
Online ISSN : 1347-5320
Print ISSN : 1345-9678
ISSN-L : 1345-9678
Materials Processing
Development of Grain Growth Promotion Technique of Ni-Based Superalloy IN713 Fabricated by Metal Injection Molding
Shinya HibinoKazushige FujimitsuRyutaro OkadaYoshimichi NomuraKenichiroh Igashira
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2021 Volume 62 Issue 3 Pages 436-441

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Abstract

High temperature strength is one of the critical technical issues to apply metal injection molding (MIM) to Nickel-based superalloy IN713. In this study, through investigating microstructure and high temperature strength of IN713-MIM materials in detail, we developed the technique to promote grain growth. In the experiments using IN713C-MIM materials, the high temperature tensile strength and the creep strength were remarkably inferior to the castings. The creep deformation mechanism of IN713C-MIM materials is revealed that grain boundary diffusion creep was dominant as the stress exponent was determined as n = 2.72. Therefore, we found out that it was important to reduce the amount of grain boundary by promoting grain growth. In the examinations aiming to reduce carbides on grain boundary, which inhibited grain boundary migration, the carbon content of IN713LC-MIM-sintered material could be suppressed to C = 0.05%. Subsequently, when IN713LC-MIM-HIP-ed material was subjected to additional heat treatment at 1280°C for 12 hr, significant grain growth was observed.

 

This Paper was Originally Published in Japanese in J. Jpn. Soc. Powder Powder Metallurgy 66 (2019) 17–22.

Demonstration of grain growth of IN713LC fabricated by Metal Injection Molding (MIM). SEM image of (a) raw powder of IN713ULC (C = 0.01%). Demonstration of grain growth of IN713LC fabricated by Metal Injection Molding (MIM). SEM image of (a) raw powder of IN713ULC (C = 0.01%). Microstructure images of (b) sintered material, (c) HIP-ed material, and (d) additional heat-treated (1280°C for 12 h) for grain growth. Fullsize Image
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© 2021 Japan Society of Powder and Powder Metallurgy
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