Papers by Author: Harun Mindivan

Abstract: The present work aims to compare the mechanical properties of Polypropylene (PP) based composites reinforced with B₄C. Maleic Anhydride Modified Polypropylene (MAPP) was added to improve the B₄C-matrix interphase. Processing has been carried out by twin-screw extrusion and injection molding. By adding the B₄C particles to the PP and PP+MAPP matrix, the yield strength, shore D hardness, microhardness and relative scratch resistance increased gradually, but PP+MAPP/B₄C composites showed better overall mechanical properties than the PP/B₄C composites. However, elongation at break values occurred for all composites dropped with the B₄C content, and PP+MAPP/B₄C composites exhibited lower elongations at break than PP/B₄C composites.

Abstract: In this work, the re-use of aluminum AA6061 chips and fly ash particles by solid-state processes (cryomilling, cold compaction and hot extrusion) is presented. The process was performed in following steps: comminuting of chips, cryomilling of comminuted chips, aluminum powders and fly ash particles, cold pressing-hot extrusion approach without sintering step. Comparative analysis of the recycled composites with fine and coarse granulated chips was focused on mechanical properties and correlated to microstructural features. The density and electrical conductivity of the recycled composites are lower than those of the unreinforced aluminum alloy due to the presence of fly ash particles. Regarding mechanical properties, the recycled composites with coarse granulated chips showed higher hardness and compressive strength than the recycled composites with fine granulated chips, but the compressive strength of the recycled composites with coarse granulated chips decreased with the increase of fly ash content.

Abstract: This study has been conducted to investigate the mechanical properties of aluminum matrix 50 vol.% SiC particle (SiCp) reinforced composites produced by a squeeze casting technique. Commercial 2618, 6082, and 7012 aluminum alloys were utilized as the matrix material. Composites were tested in as-cast and T6-tempered states. Mechanical properties of the composites were determined by hardness measurements and impact tests. As-cast composites exhibited lower hardness along with a better impact resistance than their T6-tempered states. After T6-tempering the hardness of 7012 matrix composite reached to a value of 324 HV2, which is comparable with the hardness of quenched and tempered steels.

Abstract: In this paper the tribological performance of oxide (Cr2O3, ZrO2CaO and Al203) and combined coatings applied on a commercially pure aluminum sheet were presented. Combined coatings were produced by applying Polytetrafluoroethylene (PTFE) film on the oxide coatings. Among the oxide coatings Cr2O3 exhibited the highest and Al2O3 exhibited the lowest wear resistance, in accordance with their hardness. Combined coatings exhibited superior wear resistance than oxide coatings even at heavy wear testing conditions.