Al-Mg alloys has been developed as non-heat treated die-casting alloy for automobile body parts. In the recycling process of aluminum alloy die-castings, Fe contents may increase due to the contamination of fasten parts. However, it is known that the addition of Fe to the Al-Mg alloys reduces ductility. In this study, die-castings with the shape of car body parts were fabricated, and the effect of Fe content on mechanical properties (0.2% proof stress and percent elongation) in Al-Mg alloys was investigated. As a result, 0.2% proof stress remained almost unchanged regardless of the Fe contents. On the other hand, elongation gradually decreased with increasing Fe contents. Fe and Mn-rich intermetallic compounds phase (Fe, Mn-IMC phase) such as Al6 (Fe, Mn) was found on the center area of the tensile fracture surface. This can be explained by the concept of skewed coupled zone in faceted/non-faceted eutectic alloy and the equilibrium distribution coefficient of iron in aluminum (approximately 0.05). The reduction of elongation can be attributed to the increase in Fe, Mn-IMC phase that will initiate fracture, with increasing Fe contents. When the Fe contents increased from 0.5 to 1.1%, the area fraction of the Fe, Mn-IMC phase in the fracture surface increased from nearly undetectable level to approximately 30~40%. However, the shape of Fe, Mn-IMC phase changed from plate-like to rod like. Therefore, the decrease of elongation was suppressed to the approximately 20%. Non-heat treated Al-Si alloy die-castings containing approximately 1% Fe (JIS ADC3, nearly equivalent to A360) shows the elongation of approximately 3.5% according to the handbook of the Japan Die Casting Association. On the other hand, the 1.1Fe alloy die-castings showed elongation of approximately 8%. These results suggest that, Al-Mg alloys may allow higher Fe contents than Al-Si alloys in the recycling process.
