Super Alloy Z
An alloy is a mixture of two or more metals or a metal and another material. In this case we know that Super Alloy Z contains Japanium but we don’t know if this is a metallic or nonmetallic element. When various metals are combined in a metallic alloy we could take advantage of their most desirable properties. Also new properties are created as the result of the combination. The resulting properties of the alloy can be affected by many factors that include the constituents, their proportions and the treatments done to the alloy. Among the possible treatments I could mention heat treatments, hardening, etc. Based on this fact we could understand why Mazinger is more resistant than Aphrodite-A even though they are made from the same alloy.
It is possible that there are different types of alloys among the Z family.Their properties may be much different just because different proportions or treatments were applied to the respective alloys.This minute proportion variations or addition of impurities could result in entirely different mechanical properties. Also we most remember that Mazinger-Z was designed as a battle machine unlike Aphrodite-A domestic nature. Mazinger uses a superior armored plating* than Aphrodite.
*Armored plating it’s any exterior protecting shell (normally metallic). This shell is usually thicker than it should be to protect delicate internal workings.