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Fe is considered as one of the most harmful trace elements among impurities in aluminum and its alloys due to its influence of the mechanical properties especially in elongation. It is therefore essential that the Fe content is controlled to improve quality and the toughness of aluminum alloy castings. Since demand for high strength aluminum alloy casting was significantly increased in electro materials and devices, automotive and airplane industries, it is necessary to characterize the effect of Fe and set the tolerable amount of Fe content in aluminum alloys. Al6061 alloys were prepared with compositions of 0.36, 0.45, 0.58, 0.65, 0.75, 0.81 and 0.91 wt.% Fe. Solidification characteristics were analyzed by CALPHAD (Pandat software) method. Mechanical properties such as hardness, tensile strength, elongation and fatigue strength were evaluated and compared with different Fe contents. Al13Fe4 phase increased with increasing as Fe content, however, other phases, α-AlFeSi and Mg2Si, showder a slight decrease. The higher the Fe content, the lower the electrical conductivity of the alloy due to the severe distortion of the Al matrix. As Fe content was more than specification of Al6061 alloy, 0.7 wt.%, the mechanical properties, especially, hardness and elongation were greatly influenced. The hardness is attributed to the poor densification and angular-shaped Al13Fe4 phases unevenly distributed in the α-Al matrix.

The hot deformation characteristics of an UNS No. S32205 grade duplex stainless steel with nitrogen content of 0.17 ms% was studied over the ranges of temperature from 800 to 1200 °C and strain rates from 0.001 to 1.0 s−1 at the total strain of 0.5 by the hot compression test to draw the processing map. The obtained map was discussed in combinations of microstructural observations and TEM analysis. The optimum hot working region is the temperatures from 950 to 1200 °C regardless of the strain rates without cracks and sigma precipitates.