The mechanical properties of aluminum may be improved by incorporating fine particles of aluminum oxide (Al2O3). Given that the moduli of elasticity of these materials are, respectively, 69 GPa (10 ( 106 psi) and 393 GPa (57 ( 106 psi), plot modulus of elasticity versus the volume percent of Al2O3 in Al from 0 to 100 vol%, using both upper- and lower-bound expressions.