In-situ creep law determination for modeling Spark Plasma Sintering of TiAl 48-2-2 powder. (July 2017)

• Record Type: Journal Article
• Authors: Martins, David; Grumbach, Fanny; Manière, Charles; Sallot, Pierre; Mocellin, Katia; Bellet, Michel; Estournès, Claude
• Is Part Of: Intermetallics. Volume 86(2017)
• Page Start: 147
• Page End: 155
• Publication Date: 2017-07
• Subjects: Spark Plasma Sintering -- Ti-48Al-2Cr-2Nb -- Creep -- Densification parameters -- Norton-Green model; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2017.03.006
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: Spark Plasma Sintering (SPS) is a process which allows powder densification, applying simultaneously a uniaxial external load and pulsed direct current of very high intensity through tools. This process is attracting significant attention, with a tremendous increase of studies in the metal powder densification field. Its growing popularity lies in the very fast heating rate and short cycle time driven by the Joule effect, which limits grain growth. However, this process implements different coupled electrical, thermal and mechanical phenomena. All this makes the process difficult to develop and to apply for routine industrial production, which has motivated the development of numerical simulation tools in order to understand and optimize the process. Up to now, very few models integrating the coupling between heat generation, electric transfer and mechanics have been proposed. In particular, a numerical predictive model for powder densification requires a good understanding of the mechanical behavior, in our case a viscoplastic compressive law (Abouaf mechanical model). In this article, we will discuss the characterization of the material during densification, focusing on the creep behaviors of dense and porous state materials used to simulate sintering in the Abouaf framework. Validations of the creep law parameters and also of the densification parameters will be presented and subsequently discussed. Graphical abstract: Highlights: Various in-situ SPS mechanical tests were carried out to model the powder densification in the SPS. The creep law parameters of SPS densified TiAl-48-2-2 were determined with mechanical compression tests. Identification of the Norton Green model densification functions using creep tests on porous material coupled with compaction. Identification of all the material mechanical parameters is carried out close to densification regime. Good correlation obtained between the experimental densification curve and the simulated by finite elements.