TY - JOUR ID - 64247 TI - Grain Refinement and Enhancement of Mechanical Properties of Hot Extruded Rare-Earth Containing Magnesium Alloy JO - Journal of Ultrafine Grained and Nanostructured Materials JA - JUFGNSM LA - en SN - 2423-6845 AU - Pourbahari, Bita AU - Mirzadeh, Hamed AU - Emamy, Massoud AD - School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran AD - School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran Y1 - 2017 PY - 2017 VL - 50 IS - 2 SP - 132 EP - 136 KW - Magnesium alloys KW - Rare-earth addition KW - Microstructure KW - Tensile properties DO - 10.22059/JUFGNSM.2017.02.08 N2 - The effects of rare earth addition and hot extrusion process on the grain refinement of magnesium alloy were studied. The as-cast Mg-6Al-1Zn (AZ61) alloy had the average grain size of ~ 64 µm and its microstructure consisted of α-Mg and Mg17Al12 phase. By partial substitution of Al with Gd to reach Mg-4.8Gd-1.2Al-1Zn alloy, it was observed that the Mg17Al12 phase disappeared and two new intermetallic phases, i.e. (Mg,Al)3Gd and Al2Gd, were identified. The extrusion process showed significant effects on the shape and size of intermetallics and grain size of the matrix. The grain size of the extruded Mg-6Al-1Zn alloy was refined from 64 µm to 13.4 µm as a result of recrystallization. Regarding the Mg-4.8Gd-1.2Al-1Zn alloy, the grain refinement was much more pronounced, where the extruded grain size has been refined from 698 µm to 2.4 µm (extruded at 385 °C) and 1.3 µm (extruded at 320 °C). This was related to the presence of fine and widely dispersed intermetallic phases. Tensile strength and total elongation of extruded alloys were much higher than their as-cast counterparts and the extruded Mg-6Zn-1Al alloy showed magnificent mechanical properties. The latter was related to the absence of intermetallic particles, which act as stress risers. UR - https://jufgnsm.ut.ac.ir/article_64247.html L1 - https://jufgnsm.ut.ac.ir/article_64247_2ba0bb772b32b08ea3e810b2eddb84bc.pdf ER -