A　hybrid　micron　SiC　and　carbon　nanotube　(CNT)　reinforced　AZ61　composite　is　fabricated　by　powder　metallurgy　method　and　then　extruded　at　different　extrusion　ratios　(λ　=　16,　36,　and　56,　respectively)　at　350　°C.　The　effects　of　the　extrusion　ratio　on　the　microstructural　evolution　and　mechanical　properties　are　studied　systematically.　The　results　reveal　that　both　the　porosity　and　average　grain　size　of　the　composite　reduce　with　extrusion　and　with　an　increase　in　the　extrusion　ratio.　The　basal　texture　of　the　composite　is　formed　during　hot　extrusion　and　further　enhanced　with　the　increase　in　the　extrusion　ratio.　These　changes　in　microstructural　features　lead　to　an　effective　enhancement　of　the　overall　mechanical　properties.　Particular　emphasis　is　placed　on　interrelating　the　effects　of　the　porosity　with　the　strength　of　the　composites.　In　addition,　an　empirical　expression　is　successfully　proposed　to　describe　the　relationship　between　the　porosity　and　the　strength.　©　2020　Wiley-VCH　GmbH