TY - JOUR ID - 3711 TI - Superplasticity of a fine-grained Mg–1.5 wt% Gd alloy after severe plastic deformation JO - Iranian Journal of Materials Forming JA - IJMF LA - en SN - AU - Bayat Tork, Nazanin AU - Razavi, Seyed Hossein AU - Saghafian, hassan AU - Mahmudi, Reza AD - School of Metallurgy and Materials Engineering, Iran University of Science and Technology AD - School of Metallurgy and Materials Engineering Iran University of Science & Technology AD - School of Metallurgical and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran Y1 - 2016 PY - 2016 VL - 3 IS - 1 SP - 65 EP - 74 KW - severe plastic deformation KW - Simple Shear Extrusion KW - Superplasticity KW - Shear punch test DO - 10.22099/ijmf.2016.3711 N2 - The strain rate sensitivity (SRS) of Mg–1.5 wt% Gd processed by conventional extrusion and 2 passes of simple shear extrusion (SSE) was investigated by shear punch testing. Shear punch tests were conducted at initial shear strain rates in the range of 0.003–0.3 s-1 and at temperatures in the range of 573–773 K. A fine-grained microstructure with an average grain size of about 2.5 µm, obtained after 2 passes of SSE, resulted in high SRS index (m-value) of 0.4 at 723 K. The calculated activation energy for 2 passes deformed alloy is 116 kJ/mol which is higher than the activation energy of grain boundary diffusion in magnesium (75 kJ/mol). This higher amount of activation energy can be attributed to the presence of gadolinium in this alloy. This SRS index together with an activation energy of 116 kJ/mol are indicative of a superplastic deformation behavior dominated by grain boundary sliding accommodated by grain boundary diffusion at 723 K. UR - https://ijmf.shirazu.ac.ir/article_3711.html L1 - https://ijmf.shirazu.ac.ir/article_3711_710a0994caf274828c1b5accd0a0d644.pdf ER -