چكيده به لاتين
Magnesium matrix nanocomposites have been recently studied as a noteworthy choice for engineering applications due to their low density and higher specific properties including strength, stiffness, and creep resistance. Among all the diverse methods available for metal matrix composite production, stir casting is considered as a common and relatively low cost method. Since the materials produced by casting process are not dense enough, they are usually subjected to a secondary forming process such as forging, extrusion, and rolling, which could also be used to manufacture the final products. These processes enhance the mechanical properties in addition to improving the distribution of reinforcement particles inside the matrix. In this regard, forging due to advantages such as lower operating stresses and less damage to the reinforcement phase is more noticeable. In this research, AZ31/Al2O3 nanocomposite has been fabricated by stir casting method. Then, open-die hot-forging process has been implemented on the specimens. Since most of the failures in industrial parts are due to cyclic loading and fatigue failures, the effect of applied strains during forging process has been investigated on mechanical properties and high cycle fatigue behavior in a magnesium matrix nanocomposite.
Microstructural examinations showed a partial dynamic recrystallization in forged samples. However, in the composite specimen, more dynamic recrystallization (DRX) and more uniform distribution were achieved due to the presence of reinforcement particles. Also, by adding the particles and increasing the plastic strain, the microhardness of the specimens gradually increased. Also, the nanocomposite in the uniaxial tensile and compression test shows the improvement of properties relative to the alloy. Besides, in same stress amplitudes and in lower applied strains, composite samples showed an increase in fatigue life. On the contrary, in the case of higher applied strains, during the open-die hot-forging process, alloy samples had a higher fatigue life than composite specimens.
