Mesostructural impact on the macroscopic stress state and yield locus of porous polycrystalline silver

• Published in: Materials & design 2022-07, Vol.219, p.110785, Article 110785
• Main Authors: Letz, S.A., Zhao, D., März, M.
• Format: Article
• Language: English
• Subjects: Macroscopic Behavior; Mesostructure; Representative Volume Element; Silver Films; Sintering; Yield Surface
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2022.110785

[Display omitted] •A novel continuum model for the impact of the sintered mesostructures on the macroscopic stress state and yield locus was found.•The specific pore surface area and fractional density are sufficient to predict the macroscopic stress state and yield locus.•Coincidence of the stress state and 43 % better prediction accuracy compared to literature is achieved.•The number of parameters is equal or smaller compared to present modelling approaches. The impact of real sintering structures on the macroscopic stress state and yield locus of sintered silver was investigated and a novel continuum modelling approach that predicts the macroscopic properties in an accurate, simple and efficient way was derived. Focused-Ion-Beam (FIB) tomography was utilized to study silver films, which were sintered under a wide range of processing conditions. With reconstructed three-dimensional representative volume elements (RVE), linear elastic and linear elastic–perfect plastic Finite-Element-Analyses were performed for a variety of loading states. The stress state ratios and the plastic yielding were investigated with respect to the mesostructural quantities obtained from the FIB tomography. The specific pore surface area and the fractional density were found to represent characteristic scalar measures for the sintering structure, which were further used to formulate a thermodynamic consistent continuum model for the macroscopic stress state and yield locus. An assessment of the modelling approach showed good coincidence of the macroscopic stress state with experiments and simulations from literature and a 43 % better prediction accuracy for the yield locus compared to established modelling approaches. The transferability of the model parameters to different silver sintering raw materials was partially proved by literature results and promises reduced parameterization effort.