Carbon foam characterization tensile evaluation of carbon foam ligaments

Abstract

A methodology for ligament isolation and specimen preparation for tensile testing of single ligaments from the unit cell of open-cell carbon foams has been successfully developed and implemented. Results are presented for ligaments of three different carbon foam designations. Two of them are reticulated vitreous carbon (RVC) foams of 20 and 45 pores-per- inch (ppi) coated with SiC by chemical vapor deposition (CVD) and the other is a RVC 20 ppi foam without coating.

Scanning electron microscopy and digital imaging analysis is used to analyze the fracture surfaces posts tests. The ultimate strength of each ligament evaluated. Weibull statistics is used to describe the strength distribution of ligaments. While the distribution of strengths of the carbon foam ligaments (RVC) could be described with a one-population distribution, it is found that a two-population Weibull distribution is necessary to describe the distribution of strength of the SiC coated ligaments.