Production and characterization of functionally graded B4C-TiB2-Al ceramic-metal composites

In this thesis, production and characterization of functionally graded B4C-TiB2-Al ceramic-metal composites were investigated. At the begining of the study, prepared B4C-TiB2 compositions by using TiB2 additive (%(0 – 30) by weight), were partially sintered at 1700oC/5min by spark plasma sintering method. Densities of B4C-TiB2 preforms are determined by Archimed's principle. TiB2 additives and densities of preforms were taken into consideration and functionally graded materials are designed. Designed FGMs were partially sintered under same conditions and Al-12Si alloys were infiltrated to porous FGM pre-forms at 1200oC/10min by pressureless infiltration method. Bulk density and open porosity of the composites were measured by Archiemede's method. Chemical composition were characterized by XRD, and microstructure were investigated by using SEM-EDX. Hardness were measured by mechanical test. As a result of the study, it was determined that TiB2 additive has a positive effect on sintering of B4C and hardness of B4C-TiB2-Al composite materials. Porosity of the produced FGM composite materials were measured as under %1. In FGMs, hardness changes gradually from one surface to other as being aimed.