Experimental investigations of the effect of sintering pressure and temperature on the porosity and mechanical properties of sintered silver

Purpose This paper aims to systematically investigate the effects of sintering pressure and temperature on the porosity and the corresponding tensile properties of sintered silver material. Design/methodology/approach Sintered silver test samples were manufactured using two sintering pressures (7 and 15 MPa), and two sintering temperatures (230 and 270°C), while the sintering time is kept constant at 3 min. The microstructural porosity of the sintered silver samples was analyzed using optical microscopy and image processing. Tensile tests in combination with digital image correlation measurements were performed at two strain rates (10−4 and 10−5 s−¹). Basic material properties including elastic modulus, yield stress, ultimate tensile strength and failure strains were extracted from the experimental stress−strain data, accordingly. Findings Results showed that greater sintering pressure and higher sintering temperature significantly reduce porosity, leading to improvements in elastic modulus, yield stress, ultimate tensile strength and failure strain. Statistical analysis confirmed that mechanical behavior is highly dependent on strain rate and porosity, with porosity being the dominant affecting factor. Additionally, a bilinear isotropic hardening material model incorporating porosity effects was calibrated and validated through finite element simulations. Originality/value The sintering of silver paste has recently attracted special attention as a leading joining technology for high-performance power electronics due to the exceptional mechanical and thermal properties of silver. In fact, the impact of sintering process parameters, such as pressure and temperature, on the porosity and mechanical performance of the sintered bond remains insufficiently quantified. The findings of this work provide valuable insights for optimizing sintering conditions and developing reliable constitutive models to enhance the performance and durability of power electronic modules using sintered silver interconnections.