Electron beam melting of Inconel 718: effects of processing and post-processing. Issue 5 (24th March 2018)

• Record Type: Journal Article
• Authors: Nandwana, Peeyush; Kirka, Michael; Okello, Alfred; Dehoff, Ryan
• Is Part Of: Materials science and technology. Volume 34:Issue 5(2018)
• Page Start: 612
• Page End: 619
• Publication Date: 2018-03-24
• Subjects: Additive manufacturing -- grain growth -- electron beam melting -- Inconel 718 -- Ni-base superalloy; Materials science -- Periodicals; Microstructure -- Periodicals; Metallurgy -- Periodicals; 620.1105
• DOI: 10.1080/02670836.2018.1424379
• Languages: English
• ISSNs: 0267-0836

Abstract

ABSTRACT: This study reports the effect of process temperature on microstructure evolution of electron beam melted Inconel 718. Samples fabricated at 915°C had fine grain boundary δ (∼200 nm) along with coarse intragranular δ spanning through the length of the grains. On the other hand, samples fabricated at 990°C, only had grain boundary δ along with secondary carbides. During hot isostatic pressing, the distribution of carbides governs the grain growth vs. lack of it. The samples fabricated at 990°C having grain boundary carbides had no grain growth owing to the pinning effect of carbides. In contrast, the sample processed at 915°C had significant grain growth owing to dissolution of grain boundary δ phase and absence of grain boundary carbides.