1) Is it always true for materials that if its ductility increase, its strength must decrease (and vice versa)? For example, the ductility of FCC > BCC > HCP. So does this entail that the strength of HCP > BBC > FCC? According to my (entry-level) understanding, ductility increases when: - Number of slip systems increase - The shear force required for slip decreases (such as on close-packed panes or close-packed directions). - Number of dislocations decrease (ie. less grain boundries AKA bigger grains), since dislocations impede slip. 2) It seems to me all the characteristics that increase ductility also decrease strength. Is there anything I'm missing out above which may increase ductility without decreasing strength (or even, helps increase strength)? 3) I guess I'll also ask this question: is it possible that material A has both better ductility and better strength than material B? Comparing a copper sheet and a piece of tissue paper, I'm inclined to think the answer is 'yes'.