Title : Mechanical behavior of transition metals-containing Al-Si-Cu-Mg cast alloy subjected to prolonged thermal exposure
Al-Si-Cu-Mg Cast (354) alloys are extensively used in automotive engine components owing to their outstanding performance after applying the proper heat treatment. Transition elements (Zr, Ni, and Mn) were added in different combinations and amounts in order to avoid the deterioration in mechanical properties of these Al-alloys upon the exposure to elevated temperatures for long times. The strength values (UTS and YS) obtained at room temperature for the stabilized (thermally-exposed) T5-treated conditions were comparable to those of the stabilized T6-treated conditions, and higher in the case of elevated-temperature tensile testing of the stabilized conditions.
Interestingly, the results showed that the addition of 0.75 wt.% Mn was competitive with the addition of 2 and 4 wt.% Ni with respect to the elevated-temperature and ambient temperature strength values, respectively. In addition, the Mn-containing alloy M3S exhibited improved ductility values at ambient temperature and at 250°C, compared to the Ni-containing alloys. Examination of the fracture surface of tested samples revealed the advantageous role of sludge particles in enhancing the performance of Mn-containing alloys through their resistance to the propagation of cracks that developed in many intermetallic phases. This finding is considered to be economically significant in view of the lower price of manganese compared to that of nickel.
• They will realize the importance of minor additions of certain elements in making Al-alloys suitable for elevated-temperature applications and thus overcome the problems associated with utilizing Al-alloys in applications such as: automotive engine components.
• They will be introduced to the promising role of manganese to the mechanical behavior of aluminum alloys.
• The conclusions out of the paper may open the door for a great set of research ideas.