Fundamental Aspects of Spark Plasma Sintering: II. Finite Element Analysis of Scalability

Abstract

A comprehensive three‐dimensional fully coupled thermo‐electro‐mechanical finite element framework is developed for modeling spark plasma sintering (SPS). The finite element model is applied to the simulation of spark plasma processing with four different tooling sizes and various temperature regimes. The comparison of modeling and experimental results shows that the model is reliable for qualitative predictions of the densification behavior and of the grain growth in powder specimens subjected to SPS with a given temperature regime. The conducted modeling indicates the possibility of changing the heating pattern of the specimen (warmer central areas of the specimen's volume and cooler outside areas or vice versa) depending on the size of the tooling. High heating rates and large specimen sizes elevate the temperature and, in turn, material structure gradients during SPS processing. The obtained results suggest that the industrial implementation of SPS techniques should be based on the predictive capability of reliable modeling approaches.

Field‐Assisted Sintering Technology/Spark Plasma Sintering: Mechanisms, Materials, and Technology Developments

“…[13,256] Recently, more complex geometries have been presented in the literature. [257][258][259] In many cases, the sintering behavior is neglected and the material under consolidation is considered as a dense, elastic body. This can induce large errors in terms of stress level (a sintering materials being a viscous fluid).…”

Contact resistances in spark plasma sintering: From in-situ and ex-situ determinations to an extended model for the scale up of the process

“…Indeed, the punch/die TCR has a great impact on the die-sample temperature difference and is strongly impacted by the punch/die interface pressure. The punch/die ECR and TCR, in the transversal direction, are equal to the addition of the electrical resistance of the papyex foil with the two contact resistances punch/papyex and papyex/die (17)(18).…”

“…The shrinkage curves introduced into the model (Fig. 3) are calculated by an analytic Olevsky's model for sintering [18] previously determined for our alumina powder [19]. The Table 1 Physical properties of inconel, graphite and alumina (with T in Kelvin).…”

Field Assisted Sintering Technology, Part II: Simulation

“…However, in the FAST-machine the powder material undergoes large plastic deformation. Recently [33][34][35] dealt with the densification process. In [33] an additive decomposition of the strain-rate tensor is used for the constitutive model into an elastic, viscoplastic and a thermal part.…”

“…Additionally, it is shown that larger pressures decrease the temperature gradient and the sintering temperature. [34] modeled the thermo-electro-mechanical problem using the commercial program COMSOL to analyze the scalability of Spark Plasma Sintering. In this work the influence of four different tool sizes and various temperature regimes on the grain growth and the densification behavior is studied.…”