A Study of Hybrid Aluminum Base Alloy for Bending Fatigue Resistance

Abstract: Using of aluminum and aluminum base are widely used for mechanical components. Hybrid aluminum base alloys are type of alloys with composition differs from the standard percentages. The use of these alloys instead of steel alloys have increasing expansion due to their low weight to toughness ratio and their superior mechanical properties. Fatigue resistance is one of the important properties due exerting most of the mechanical components to cyclic and variable loadings. In this study a hybrid aluminum base alloy has a compositions (Aluminum 85%, Silicon 10% and Chrome5%) is used to investigate its mechanical properties and fatigue resistance under constant completely reversed cyclic loadings under bending rotation. The results identified a relatively poor bending fatigue resistance under low fatigue regime, with relatively long fatigue life under low bending loading compared with the other hybrid aluminum base alloys with average bending stress*fatigue life of (214,5392 MPa. cycle). The results also confirm the applicability of AL-Bedhany Energy Fraction of Damage Accumulation (EFDA) fatigue damage theory, which depends on the area under S-N curve under the average loading level in MPa cycle. The percentages of errors between 8.7% to -20.5% for the predicted fatigue life according to the gradual propagation of the fatigue cracks of this alloy appears clearly at the fracture regions due to alloy’ malleability. This makes this alloy suitable only for manufacturing the shafts with relatively low bending stress.