Fine-grained Mg-1Mn-0.5Al-0.5Ca-0.5Zn alloy withhigh strength and good ductility fabricated by conventional extrusion
(1. Joint International Laboratory for Light Alloys, College of Materials Science and Engineering,Chongqing University, Chongqing 400044, China;
2. Guizhou Anda Aviation Forging Co., Ltd., Anshun 561005, China)
2. Guizhou Anda Aviation Forging Co., Ltd., Anshun 561005, China)
Abstract: Mg-1Mn-0.5Al-0.5Ca-0.5Zn (wt.%) alloy was fabricated by conventional extrusion at 673 K with an extrusion ratio of 25:1, followed by aging at 473 K. The microstructure was characterized by scanning electron microscopy, electron back-scattered diffraction, and transmission electron microscopy. The mechanical properties were determined by the tensile test. The peak-aged sample shows fine recrystallized grains with an average grain size of 1.7 μm. Area fraction of Al-Ca particles in the alloy increases significantly after peak aging. Meanwhile, botháa？ andác+a？ dislocations were observed to remain in the alloy after hot extrusion. Thus, the peak-aged sample exhibits simultaneously high strength and good ductility with the ultimate tensile stress, tensile yield stress, and tension fracture elongation of 320 MPa, 314 MPa, and 19.0%, respectively.
Key words: Mg-Mn-Al-Ca-Zn alloy; fine grain; precipitate; strength; ductility