The presentworkdealswiththemicrostructureandroomtemperaturemechanicalpropertiesofpure magnesium andcastAZ80nano-composites.Towardthisend,differentweightpercentofSiC reinforcementnano-particles(1.5,2.5and3.5)wereaddedhomogenouslyintothematrixemploying stir castingmethod.ItwasfoundthattheSiCnano-particlescanreducethegrainsizeofmagnesium matrices, significantly.Thepresenceofnano-particlesassistedinimprovingthehardnessvalues.In addition, thetensilestrengthandtheductilityvaluesincreasedbyincreasingtheSiCcontent.Thiswas reasoned consideringtheoccurrenceofgrainrefinement, Orowanstrengthening,coefficient thermal expansionmismatchofthematrix-particles,andtheloadbearingeffect.However,therewasan optimum SiCcontentbeyondwhichthestrengthandformabilityofthematerialsweredecreased.The latter wasattributedtotheagglomerationofSiCparticlesinthemicrostructureofthecomposites.Inline to these findings, thecompressiontestsresultsalsoindicatedcontinuousimprovementofultimate compressivestrength.Thecompressivestress-straincurveswerealsoemployedtostudythework hardening behaviorofthematerials.