To the best of our knowledge, the general approach of designing alloys with specified mechanical properties does not exist. This is due to the unresolved problem of analysing the set of heterogeneous variables that affect the mechanical properties along its production line from the smelting of the alloy to the manufacture of the final product. Here, we show that in principle this problem can be solved by analysing all the strengthening mechanisms in a common reference frame with reference to the single factor namely, the generalized degree of metallicity and covalence, which characterizes the entire interatomic bonds in all phases of the alloy. Such factors are able to reflect the results of hardening by various mechanisms because of the correlation with the mechanical properties. From the energy view point, these factors correspond to the proportion of the metallic and covalent bonds energy in the total energy of all chemical bonds in the alloy. Based on the approach being developed, we considered a method for predicting new doping systems for dispersively strengthening aluminum alloys according to the criterion of a given strength and have considered the methodology of optimizing chemical composition in steel smelting which is used for mass production of parts according to the criterion of the desired mechanical properties obtained due to solid solution hardening.