5083 H116 vs H321 aluminum difference are both tempers of the same 5083 aluminum alloy, but their temper designations reflect different processing and property requirements. The chemical composition of the base alloy remains essentially the same, while the temper treatment influences mechanical behavior and suitability for particular applications. H116 is commonly associated with strain-hardened marine plate that meets specific requirements related to resistance to exfoliation corrosion and intergranular corrosion, making it particularly relevant to marine service.