Hardness–Yield Strength Relationships in Al-Zn-Mg(-Cu) Alloys

Mean pressure developed during Vickers and Rockwell hardness testing of Al-Zn-MgCualloys is reviewed. Relationships between mean pressure and yield strength are introduced for these alloys by using both Vickers and Rockwell hardness data from the literature. Results have shown that the slope of the mean pressure–yield strength relationships is 0.355 for Vickers tests and 0.264 for Rockwell B tests. The y-intercepts calculated for best fits are all negative, implying that the representative strains in both tests have exceeded the yield strain. Results also have indicated that mean pressure is affected by the indenter geometry and therefore is not a universal hardness number.