Microstructure and compression behavior of Ag–W metal matrix composite produced from core–shell powder by spark plasma sintering: case study

Metal matrix composites represent an interesting class of materials with an exclusive combination of properties. In this study, a unique Ag–W metastable metal matrix composite was produced from W@Ag core–shell powders using a spark plasma sintering technique at a temperature of 700 °C and a pressure of 80 MPa. The microstructures of a default powder and as-produced composite were observed by scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy and electron backscatter diffraction. As expected, the composite is characterized by a dual microstructure: a soft matrix of pure Ag with a submicrometer grain size reinforced by W particulates with a grain size of up to 30 μm. In addition, tensile and compression tests were performed with a deformation rate of 10^–3 s⁻¹ at ambient temperature. The value of the compression yield stress of Ag–W MMC is higher than the compression yield stress of pure Ag by approximately 467%. Observation of the microstructure of the deformed composite material revealed that the interface between the matrix and the reinforced particles is the weakest place, which is a key factor influencing the performance and properties of the composite material.