Elastic constants of porous silver compacts after acid assisted consolidation at room temperature

Acid assisted consolidation (AAC) is a technique that provides elevatedlevels of cohesiveness to silver powder compacts without recourse to a high temperature treatment. Ultrasonic techniques were used to measure the elastic constants of high purity silver compacts as a function of several processing variables. The elastic moduli of untreated (NT) samples were found to be significantly lower than those of samples that had undergone AAC and compacted at the same pressure. Post compaction sintering increases the elastic constants of both AAC and NT samples. The results indicate that the elastic constants are dependent not only on the density that was attained but also on the processing route that was followed. The elastic constant of a porous metal, M, can be expressed as M = M₀g, where M₀ is the elastic modulus of the bulk metal, g is a geometrical factor that reflects the interparticle contact area and is a quality factor that depends on the nature of the interparticle interfaces. The results suggest that sound wave velocity is a parameter more appropriate than density for predicting the elastic moduli of porous metallic compacts.