Applied Composite Materials

Carton, E.; Stuivinga, M.; Keizers, H.; Verbeek, H.; van der Put, P.

doi: 10.1023/A:1008802404304pmid: N/A

Shock compaction was used in the fabrication of high temperature ceramic-based materials. The materials' development was geared towards the fabrication of nozzles for rocket engines using solid propellants, for which the following metal-ceramic (cermet) materials were fabricated and tested: B4C-Ti (15 vol.-%), B4C-Al, and TiB2-Al, with an Al content typically between 15–20 vol.-%. Here, the B4C-Ti was only shock-compacted, while the other two cermets were shock compacted followed by melt infiltration with Al.

Taipalus, R.; Harmia, T.; Friedrich, K.

doi: 10.1023/A:1008858832318pmid: N/A

This study deals with the mechanical and electrical properties of polypropylene (PP)/ polyaniline (PANI)-complex blends and their short glass fibre (GF) composites. In particular, the surface resistivity, the electrical conductivity and its profile were characterized. Tensile modulus, tensile strength and impact resistance of the materials were also measured as a function of GF- and PANI-complex content. The miscibility and microstructure of the blends could be studied by using light optical and scanning electron microscopy. While a steady increase in tensile modulus with increasing GF content was observed in all material combinations, an improvement in the tensile strength could only be achieved in case of the glass fibre reinforced unmodified PP-matrix composites. The conductivity of the materials increased with increasing PANI-complex content. The low percolation threshold for conductivity could be explained by the formation of a PANI-complex network near the surface of the samples.

Remond, Y.; Wagner, C.

doi: 10.1023/A:1008893820798pmid: N/A

This paper deals with the measurement of subsurface damage of composite materials after braking situations. Several carbon–carbon composites materials have been studied and tested under industrial braking conditions. Two damage measurement methods were used to estimate the braking effects on the mechanical behaviour of these materials. In particular, a meso-hardness test has been adapted to the heterogeneity of carbon–carbon composite and to their macro-porosity. Depending on the type of material, the results show that meso-hardness is a good indicator of local behaviour at a small depth under the surface. For one C–C composite, reinforced with long random fibers, we measure the evolution of damage as a function of the distance of the braking surface. Another original compression-bending test was also used, which confirms this damaged subsurface effect before wear occurs.