The demand for simultaneous increase in stiffness and weight reduction at recent product design for car body parts makes particle reinforced aluminum matrix composites (AMCs) an attractive engineering material. Therefore, different boron compounds for lightweight applications were evaluated regarding wettability and stiffness and were chosen for composite manufacturing via melt stirring process. The challenge is to obtain homogeneous particle distribution and porous free composites. Therefore, melt stirring equipment for manufacturing composites with homogenous particle distribution has been developed on a laboratory scale. The amount of porosity, which typically occurs at melt stirring, is reduced by adapting partial vacuum during particle feeding and stirring. AMCs with up to 15ˆvol.% of boron carbide (B4C), aluminum diboride (AlB2) and boron (B) particles are produced via melt stirring and investigated concerning Young’s modulus and particle distribution. The latter depends on wettability of liquid aluminum and particle material and on applied shear forces adjusted by different stirring parameter and impeller geometries. Even though wettability of B4C is worse than AlB2, high shear forces enable homogenous particle distribution and same content of incorporated particles for B4C as well as for AlB2. Particle distribution is evaluated by using statistical analysis and mechanical characterization of cast samples showed that Young’s modulus increases significantly with increasing particle content and amount of incorporated particles depends more on applied shear forces than on wettability of B4C, AlB2 and B with molten aluminum.