Mechanical properties and microstructure of B4C-NanoTiB2-Fe/Ni composites under different sintering temperatures

In the present article, a B4C composite with 10 vol% of titanium diboride nanoparticle (TiB2) was separately mixed with a 1, 2, 3, 4 and 5 vol% iron or nickel additive and various values of carbon (as a binder) in a powerful mill in an isopropanol environment. After drying, the mixture was primary formed by cold pressing. The obtained parts were sintered at 2150 °C and 2250 °C. The effect of additives and sintering temperatures on the physical and mechanical properties and microstructure of the composite was investigated. The results showed that growth in additives percentage raises the shrinkage and the relative density of the specimens and reduces the porosity. The highest values obtained for hardness, elastic modulus and fracture toughness were 36.33 GPa, 526.38 GPa and 5.52 MPa m1/2, respectively. Scanning electron microscope (SEM) images of the microstructure of the specimens showed uniformity of elements distribution and confirmed the proper sinterability of the specimens at 2150  °C and 2250 °C.