Microstructure and Mechanical Properties of EK30 Alloy Synergistically Reinforced by Ag Alloying and Hot Extrusion for Aerospace Applications

• Published in: Materials Vol. 15; no. 23; p. 8613
• Main Authors: Zhang, Daohe, Zhao, Sicong, Chen, Hongtao, Feng, Yicheng, Guo, Erjun, Li, Jingfang
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 02-12-2022; MDPI
• Subjects: Aerospace materials; Alloying; Alloys; Beta phase; Ductility; Dynamic recrystallization; Elongation; Equal channel angular pressing; Fractures; Grain growth; Grain refinement; Grain size; High temperature; Hot extrusion; IEECAP; Magnesium alloys; Magnesium base alloys; Mechanical properties; Mg-RE-Ag alloy; Microstructure; Nucleation; Plastic deformation; Scanning electron microscopy; Silver; Specialty metals industry; Technology application; Tensile properties; Ultimate tensile strength; United Kingdom > UK; United States > US; microstructure; Mg-RE-Ag alloy; mechanical properties; IEECAP
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15238613

Enhancing the mechanical properties of magnesium alloys to meet the urgent need for their lightweight applications in the aerospace field has always been a great challenge. Herein, the effect of Ag on the microstructure and tensile properties of the Mg-2.5Nd-1.0Sm-0.4Zn-0.1Ca-0.5Zr (EK30) alloy prepared by integrated extrusion and equal-channel angular pressing is studied. The microstructure of as-extruded alloys consists of
-Mg grains and the
phase. The addition of Ag increases the
-phase content. The
phase can promote dynamic recrystallization by inducing a particle-stimulated nucleation mechanism and inhibiting grain growth, which leads to grain refinement and texture weakening. At 250 °C, the ultimate tensile strength of the EK30-2.0Ag alloy (225.9 MPa) increased by 13.8% compared to the Ag-free alloy (198.4 MPa). When the tensile temperature increased from 25 °C to 250 °C, the ultimate tensile strength of the EK30-2.0Ag alloy decreased by 14.3%, from 263.7 MPa to 225.9 MPa. Notably, the addition of Ag slightly reduced the elongation of the alloy at 250 °C; the elongations of the EK30-2.0Ag alloy and the EK30 alloy are 41.5% and 37.0%, respectively. The elongation of the EK30-2.0Ag alloy increased from 22.7% at 25 °C to 52.7% at 275 °C. All alloy tensile fractures exhibited typical plastic fracture characteristics. This study provides an effective way to enhance the high-temperature mechanical properties of magnesium alloys by Ag alloying and a special severe plastic deformation method.