Deformation Characteristics of Recycled AZ91 Mg Alloy Containing Oxide Contaminants

Abstract

Deformation characteristics of a recycled AZ91 Mg alloy, obtained from machined chips by solid state recycling, were investigated by conducting tensile tests between room temperature and 773 K in the strain rate range of 3:3 Â 10 À2 -3:3 Â 10 À4 s À1 . Tensile properties of the recycled specimen were compared with those of a reference specimen. The elongation to failure of the recycled specimen was lower than that of the reference specimen, except at room temperature and 753 K with 3:3 Â 10 À4 s À1 . The recycled specimen contained oxide contaminants whose size was À2 mm. Such oxide contaminants were responsible for the reduction in elongation to failure. The cavity formation due to the oxide contaminants was analyzed using existing theoretical models, and experimental results were compared with analytical results.

Effects of Oxide Fragments on Microstructure and Mechanical Properties of AA6061 Aluminum Alloy Tube Fabricated by Thermomechanical Consolidation of Machining Chips

“…This finding is supported by the EDS mapping results of the oxide particles showing that the Mg element is detected in the oxide particles, as shown in Figure 4 b. Similar oxide particles were also observed in the microstructures of samples produced by hot extrusion of compacts of AZ91 magnesium alloy scraps [ 19 ] and 5083 aluminum alloy chips [ 13 ] due to the breaking of oxide films.…”

“…The rationale behind solid state recycling technique is based on the severe plastic deformation, introducing large shear deformation to enhance physical and metallurgical bonding. To date, an increasing number of solid-state recycling processes have been reported including ball milling, sintering [ 7 ], hot pressing [ 8 , 9 , 10 ], spark plasma sintering [ 11 ], hot extrusion [ 3 , 5 , 6 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ], equal channel angular pressing [ 25 , 26 , 27 , 28 , 29 ], cycling extrusion compression [ 30 , 31 ], friction stir extrusion [ 32 , 33 ], high-pressure torsion [ 34 ], and screw extrusion [ 35 ].…”

Microstructure and high tensile strength of Mg–10Gd–2Y–0.5Zr alloy by solid-state recycling

“…Oxide contaminants from the surfaces of chips were dispersed within the grains or at grain boundaries after extrusion deformation [5]. Oxide contaminants were believed to be the sites for stress concentration and cavity nucleation [20]. Thus, the cavity nucleation that occurred at grain boundaries and within the grains adversely affected the elongation property.…”

Microstructure and tensile properties of consolidated magnesium chips

“…In this context SSR of Mg alloys is of paramount interest and most of the research works focus on the tensile strength of recycled products [4,5,[8][9][10]. In addition, some studies are focused on the role of oxide contaminants on the resulting microstructure and properties [11]. However, to the best of our knowledge there is no publication available on the strength asymmetry and strain hardening characteristics of such recycled materials.…”

“…recycling of discarded machined chips of magnesium and development of sustainable manufacturing process. The interest in chip consolidation may be seen as follows [2][3][4][5][7][8][9][10][11][12][13]:…”