Document Type: Original Article
Faculty of Mechanical Engineering, Semnan University
In the presented article, the temperature effect was studied on creep properties and fracture behaviors of AlSi12Cu3Ni2MgFe aluminum-silicon alloys, unreinforced and reinforced with SiO2 nano-particles. For such objective, standard specimens were fabricated by gravity casting and stir-casting methods, for aluminum alloys and nano-composites, respectively. Then, force-controlled creep testing was performed on standard specimens at 250, 275 and 300°C, under 100 MPa. Then, to find failure mechanisms, the fracture surface of test samples was also analyzed by the field emission scanning electron microscopy. Experimental results depicted the temperature changed creep behaviors of both materials, effectively. Moreover, a significant improvement in creep properties was observed by reinforcing the aluminum matrix with nano-particles, besides a heat treatment process. Such an increase in the creep lifetime was higher at 300°C. In addition, the fracture surface investigation of both materials implied the same brittle behavior, with quasi-cleavage marks. The failure location changed from inside the intermetallic phase into boundaries of the intermetallic phase, in the nano-composite.