, et al.. Contact resistances in spark plasma sintering: From in-situ and ex-situ determinations to an extended model for the scale up of the process. Journal of the European Ceramic Society, Elsevier, 2017, vol. 37 (n°4) b s t r a c tHeating in spark plasma sintering is a key point of this manufacturing process that requires advanced simulation to predict the thermal gradients present during the process and adjust them. Electric and thermal contact resistances have a prominent role in these gradients. Their determination is difficult as they vary with pressure and temperature. A calibration method is used to determine all of the contact resistances present within tools of different sizes. Ex situ measurements were also performed to validate the results of the in-situ calibrations. An extended predictive and scalable contacts model was developed and reveals the great importance and diversity of the contact resistances responsible for the general heating of the column and high thermal gradients between the parts. The ex/in situ comparison highlights a high lateral thermal contact resistance and the presence of a possible phenomenon of electric current facilitation across the lateral interface for the high temperatures.

Abstract. The main deformation mechanisms of shape memory alloys (SMA) are related to martensitic transformation and/or martensitic rwrientation. These phenomena lead to heat production resulting from the transformation andlor from internal dissipation processes. As the SMA behaviour is strongly temperature dependent, its modelling has to take into account thennomechanical coupling. A 3-dimensional finite element code has been designed for that purpose. The quasi-static mechanical behaviour is described through the temperature dependent elastohysteresis model. Large displacements and large deformations are considered. The numerical problem is strongly non-linear and an implicit resolution scheme has been adopted. Two coupled thennomechanical calculations are presented. The first one deals with the one-way memory effect of a cantilever beam. The second one simulates the non-stationary thermal and mechanical fields of this beam during a near-adiabatic pseudoelastic bending.

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