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In the current study the effect of different temperatures on the aging behaviour of a functionally gradient material was investigated to observe the variation of hardness with respect to the aging time. To do this, the functionally-gradient-material (FGM) specimens, containing boron carbide and aluminum alloy, were produced with hot pressing. Three different layers were used in the FGM samples. Then the macro and micro examinations were carried out to observe the interface between the layers, the porosity, the grain size and probable cracks in these samples. After that the specimens were solutionized at 470 degrees C for I h. Next, the artificial aging at 100 degrees C, 120 degrees C and 150 degrees C was applied to the FGM specimens for 96 h. During the aging treatment, the Brinell hardness measurements were made on the samples at certain intervals. Moreover, three-point bending tests were also carried out to clarify the influence of the aging treatment on the strength of the FGM. Experimental results indicated that the highest hardness values were obtained at 120 degrees C after the aging period of 48-65 h. The aged specimens exhibited higher bending strength than the solutionized specimens., Research Fund of TubitakTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [110M034]; TubitakTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK), This work was supported by the Research Fund of Tubitak, Project # 110M034. The authors are thankful to Tubitak for its support.

The potential of silicon carbide reinforced Functionally Gradient Material (FGM) to be used as armor material was investigated under the impact of armor piercing projectile. For this purpose, the SiC-Aluminum Alloy (AA) 7075 functionally graded composite at different thicknesses was produced from the metallic and ceramic powders via powder metallurgy method. Before the ballistic testing, the precipitation hardening behavior of the samples was determined. And also, the microstructural characterizations of the samples were done with the aid of microscopy techniques. Next, the FGM samples were tested using armor piercing projectile to analyze their impact behavior. In the produced samples, some pore formation was detected. The ballistic experiments showed that the investigated FGMs (up to a thickness of 25 mm) did not withstand the impact of the projectile. At the tested samples, some major cracks and plug formation were detected at macrolevel while there were some microcracks, deformed and elongated grains in the regions near to the deformation zone of the samples. (C) 2013 Elsevier Ltd. All rights reserved., Research Fund of TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [110M034], This work was supported by the Research Fund of TUBITAK, Project # 110M034. The authors are thankful to TUBITAK for its support. Moreover, they also thank to MKE Silahsan A.S. (Kirikkale) for its support on the ballistic tests.

In this study, the functionally graded materials (FGMs) bearing three layers were produced via hot pressing to investigate their ballistic performances against 7.62 mm armor piercing (AP) projectile. In the FGM samples, the bottom layer was considered as unreinforced AA7075 alloy, whereas the middle and top layers were made of the AA7075 composite layers having various proportions of B4C particles. Prior to the ballistic testing, the hardness change in the layers with respect to aging time at different temperatures was determined. And then, the ballistic testing of the samples was performed at a ballistic laboratory using 7.62 mm AP projectile. In the ballistic testing, five separate specimens for each FGM group having fixed composition and thickness were used. The experimental results showed that the ballistic impact resistance of the investigated FGMs increased with increasing boron carbide content and the thickness in the layers. Moreover, there were no separations observed between the layers in the failed samples., This work was supported by the Research Fund of TUBITAK, Project # 110M034. The authors are thankful to TUBITAK for its support. Moreover, they also thank MKE Silahsan A. S. (Kirikkale) for its support on the ballistic tests., TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [110M034]

In the current study the effect of different temperatures on the aging behaviour of a functionally gradient material was investigated to observe the variation of hardness with respect to the aging time. To do this, the functionally-gradient-material (FGM) specimens, containing boron carbide and aluminum alloy, were produced with hot pressing. Three different layers were used in the FGM samples. Then the macro and micro examinations were carried out to observe the interface between the layers, the porosity, the grain size and probable cracks in these samples. After that the specimens were solutionized at 470 degrees C for I h. Next, the artificial aging at 100 degrees C, 120 degrees C and 150 degrees C was applied to the FGM specimens for 96 h. During the aging treatment, the Brinell hardness measurements were made on the samples at certain intervals. Moreover, three-point bending tests were also carried out to clarify the influence of the aging treatment on the strength of the FGM. Experimental results indicated that the highest hardness values were obtained at 120 degrees C after the aging period of 48-65 h. The aged specimens exhibited higher bending strength than the solutionized specimens., Research Fund of TubitakTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [110M034]; TubitakTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK), This work was supported by the Research Fund of Tubitak, Project # 110M034. The authors are thankful to Tubitak for its support.

The potential of silicon carbide reinforced Functionally Gradient Material (FGM) to be used as armor material was investigated under the impact of armor piercing projectile. For this purpose, the SiC-Aluminum Alloy (AA) 7075 functionally graded composite at different thicknesses was produced from the metallic and ceramic powders via powder metallurgy method. Before the ballistic testing, the precipitation hardening behavior of the samples was determined. And also, the microstructural characterizations of the samples were done with the aid of microscopy techniques. Next, the FGM samples were tested using armor piercing projectile to analyze their impact behavior. In the produced samples, some pore formation was detected. The ballistic experiments showed that the investigated FGMs (up to a thickness of 25 mm) did not withstand the impact of the projectile. At the tested samples, some major cracks and plug formation were detected at macrolevel while there were some microcracks, deformed and elongated grains in the regions near to the deformation zone of the samples. (C) 2013 Elsevier Ltd. All rights reserved., Research Fund of TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [110M034], This work was supported by the Research Fund of TUBITAK, Project # 110M034. The authors are thankful to TUBITAK for its support. Moreover, they also thank to MKE Silahsan A.S. (Kirikkale) for its support on the ballistic tests.

In this study, the functionally graded materials (FGMs) bearing three layers were produced via hot pressing to investigate their ballistic performances against 7.62 mm armor piercing (AP) projectile. In the FGM samples, the bottom layer was considered as unreinforced AA7075 alloy, whereas the middle and top layers were made of the AA7075 composite layers having various proportions of B4C particles. Prior to the ballistic testing, the hardness change in the layers with respect to aging time at different temperatures was determined. And then, the ballistic testing of the samples was performed at a ballistic laboratory using 7.62 mm AP projectile. In the ballistic testing, five separate specimens for each FGM group having fixed composition and thickness were used. The experimental results showed that the ballistic impact resistance of the investigated FGMs increased with increasing boron carbide content and the thickness in the layers. Moreover, there were no separations observed between the layers in the failed samples., This work was supported by the Research Fund of TUBITAK, Project # 110M034. The authors are thankful to TUBITAK for its support. Moreover, they also thank MKE Silahsan A. S. (Kirikkale) for its support on the ballistic tests., TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [110M034]