Sintering Behavior of Al-B4C Powder Material and its Phase Evolution during Rolling

MMC samples consisting of aluminum and boron carbide were prepared out of sintered powder. In a first step, the sintering behavior of the so-produced slab was investigated. Subsequently the samples were hot-rolled in a 2-high rolling mill to 1/6 of the initial diameter. To evaluate microstructure and chemical composition of the emerging phases of the produced composites, X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) were applied. Mechanical properties of the specimens were investigated by tensile and hardness tests. To analyze the neutron attenuation behavior JEN-3 test was applied. This tool is a neutron absorption testing equipment which is used in the industry for non-destructive material inspection. Significant shrinkage does not occur however sintering has functioned properly as can be seen by the occurring sinter necks after the heat treatment. Furthermore, the density after rolling is 100%. Therefore, it can be stated that the combination of temperature and mechanical deformation leads to a full dense material. This is also approved by the results of the tensile tests. The microstructure of the MMC material showed the B4C particles properly distributed in the aluminum matrix. In the diffusion zone between Al und B4C different phases with different chemical compositions appeared. The so characterized phases include but are not limited to AlB2 and AlB3. Nevertheless, the neutron attenuation behavior is not influenced of these.