抄録
The purpose of this study is to investigate the influence of microstructure on strength properties of Al-Mg-Zn series alloy under corrosive environment. Zn was added to Al-Mg alloy of AC7A, to improve its mechanical properties. In this study, weight fraction of Zn addition was controlled to 3.1, 3.4 and 4.1 wt%. Appropriate conditions of solution treatment and aging (T6) treatment were conducted to equate its strength with that of AC4CH which is the conditional material of aluminum wheel. The heat treated material was machined to tensile specimen with circumferential V-notch. Tensile strength under corrosive environment was characterized by constant load tensile test with 1wt% of NaCl solution of corrosive media. Behavior of hydrogen generation was evaluated by fixed point observation. Test results were as follows; tensile strength decreased under corrosive environment and the amount of hydrogen generation was increased with increase of weight fraction of Zn. Microstructure observation showed that Mg and Zn were segregated around grain boundary and fracture surface was selectivity formed around segregation.
