Effects of reduced extrusion temperature on microstructure and mechanical properties of Mg–6Zn–0.5Zr alloy. (January 2023)

• Record Type: Journal Article
• Authors: Lv, Shuhui; Yang, Qiang; Lv, Xiaoling; Meng, Fanzhi; Qiu, Xin
• Is Part Of: Materials & design. Volume 225(2023)
• Publication Date: 2023-01
• Subjects: Magnesium alloys -- Reduced extrusion temperature -- Transmission electron microscopy (TEM) -- Intermetallic phase -- Mechanical properties; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2022.111568
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: ZK60 alloy was prepared by direct extrusion at an ultra-low temperature of 180 °C. The studied sample contains fine grains, strong texture and lath-like sub-grains. Ultra-low extrusion temperature increased fine precipitates in matrix. The alloy exhibits significantly high UCS of ∼675 MPa based on a CYS of ∼310 MPa. The alloy has excellent strength-ductility balance with a high TYS of ∼400 MPa. Abstract: Improving the strength of the commercial ZK60 alloys plays a key role in promoting their wide applications. In this work, a ZK60 alloy was prepared by conventional direct extrusion at an obviously reduced temperature of 180 °C. Compared with ZK60 alloys directly extruded at high temperatures (>300 °C), the studied alloy has finer dynamic recrystallized (DRXed) grains with the average size of ∼1.7 μm, stronger typical fiber texture and more profuse lath-like sub-grains. In addition, the ultra-low extrusion temperature increased dynamic precipitates (rod-like Mg4 Zn7 and MgZn2 ) in DRXed grains. After aging, a great many of nanosized precipitates formed in both DRXed grains and non-recrystallized grains, and relatively coarse MgZn2 particles precipitated on sub-grain boundaries. As a result, the aged ZK60 alloy exhibit significantly high ultimate compressive strength of ∼675 MPa on the basis of high yield strength of ∼310 MPa, indicating a significant strain hardening capability. Meanwhile, it has excellent strength-ductility balance and a weakened tension-compression yield strength asymmetry under owning a high TYS in order of ∼400 MPa.