Additive manufacturing of the high-strength nickel base superalloys using the metal 3D printer

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06799
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Material processing/Microstructural control engineering
• Research Institution: Tokyo Metropolitan University
• Principal Investigator: Kakehi Koji 首都大学東京, システムデザイン研究科, 教授 (70185726)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: ニッケル基超合金 / 積層造形 / 選択的レーザー溶融法 / 電子ビーム溶融法 / 高温強度 / デンドライト組織 / 凝固偏析

Outline of Final Research Achievements

The effects of build direction and heat treatment on the creep properties of an Ni-base superalloy fabricated by additive manufacturing were examined at 650 °C. The creep rupture lives and ductilities of materials produced by additive manufacturing were lower than those of conventionally wrought material. The horizontal-direction specimen exhibited inferior creep life and worse ductility than the vertical-direction specimen because of the orientation of the interdendritic δ-phase precipitates, which were arrayed vertical to the stress axis in the former specimen. The morphology and the presence of a row of interdendritic δ-phase precipitates with incoherent interfaces were found to affect the materials’ creep life and ductility.

Free Research Field

ニッケル基超合金の積層造形

Academic Significance and Societal Importance of the Research Achievements

選択的レーザー溶融法で作製した積層造形Ni基超合金において，プロセス過程の急熱急冷の繰り返しに起因するデンドライト凝固偏析により高温強度特性劣化が生じ，そのメカニズムを明らかにし，その課題解決の方向性を示した．