Mechanical properties of cellular solids produced from hollow stainless steel spheres

Abstract

Mechanical properties of cellular hollow sphere structures are studied in this work. The material was fabricated by coating the metallic powder slurry on expanded polystyrol (EPS) spheres, drying, forming under compression, debinding, and final sintering of the spheres to each other. Longitudinal elastic wave velocities were measured using ultrasound phase spectroscopy while compression tests were carried out up to a homologous temperature of 0.6. Dependence of the relative Young's modulus on the relative density is similar to conventional open-cell foams. Compression stress-strain plots show the three stages of elastic deformation, plateau, and densification. With increasing temperature the overall level of the compressive stress-strain plots shifts to lower stresses. The hollow sphere solids show slightly better high temperature strength in comparison to the base metal. However, due to the considerable scatter in the experimental data points, this improvement seems to be insignificant. Structural observations on samples deformed to within the plateau region clearly show the heterogeneous progress of deformation

Temperature Effects on the Deformation Behavior of High‐Density TRIP Steel and Particle‐Reinforced TRIP Steel/Zirconia Honeycombs Under Quasi‐Static Compressive Loading

“…Based on the knowledge of the deformation mechanisms and the crush performance at different ambient temperatures, these materials will enable the engineers to use their full potential at certain loading conditions and environments. A number of previous studies have concerned with the investigation of the compressive stress–strain behavior of foams, hollow sphere and honeycomb structures at elevated temperatures in order to prove their applicability as isolators, heat exchangers or heat shields in burning chamber and exhaust systems . As expected, the temperature increase mostly caused a significant decrease in compressive yield and plateau strength of the cellular structure associated with the temperature‐sensitive flow behavior of the bulk material.…”