Recent Progress and Development in Extrusion of Rare Earth Free Mg Alloys: A Review

Abstract

Mg and its alloys are the lightest structural metals available and are extremely attractive for applications as lightweight components, particularly in the automobile, electronic, and aerospace industries. The global market for wrought Mg alloys has steadily expanded over the past decade. And numerous studies have been carried out to meet this increasing demand of high-performance Mg alloys. However, Mg extrusion alloys have had a very limited usage so far. To overcome existing industrial challenges, one desirable approach is the development of low-cost rare earth (RE) free Mg extrusion alloys with superior mechanical properties. This review will introduce the recent research highlights in the extrusion of Mg alloys, specifically focusing on low-cost RE-free Mg alloy. The results from both the literature and our previous study are summarized and critically reviewed. Several aspects of RE-free Mg extrusion alloys are described in detail: (1) novel alloying designs including Mg-Al-, Mg-Zn-, Mg-Ca-, Mg-Sn-, and Mg-Bi-based alloys, (2) advanced extrusion techniques, and (3) extrusion-related severe plastic deformation (SPD) processing. Accordingly, considering the large gap in mechanical properties between the current RE-free Mg alloys and high-performance aluminum alloys, new alloy design, processing route control, and recommendations for future research on RE-free Mg extrusion alloys are also proposed. We hope this review will not only offer insightful information regarding the extrusion of RE-free Mg alloys but also inspire the development of new Mg extrusion technologies.

Wear Behavior of the Multiheterostructured AZ91 Mg Alloy Prepared by ECAP and Aging

“…Due to the well-known Hall-Petch law, the ultrafine/nanograined Mg alloys are intensely pursued to address the issues of poor strength and ductility [14][15][16][17][18][19]. In recent years, the microstructure design based on the development of the heterostructure provides a new way for the high-performance materials [20][21][22][23].…”

Enhancing the Mechanical Properties of AZ80 Alloy by Combining Extrusion and Three Pass Calibre Rolling

“…Owing to the low density and relatively abundant resources of magnesium (Mg), Mg alloys have great potential in lightweight structural applications to meet the increasing lightweight requirement for less pollution emission as well as better fuel efficiency [1,2]. However, their poor mechanical performance inhibits their wider commercial application.…”

“…In addition, some newly modified processing technologies such as low temperature slow speed extrusion (LTSS-E) [10] and double extrusion (DE) [11,15], were also explored as choices for producing high performance Mg alloys. However, these processing technologies are inapplicable to commercialize because of limited dimensions, low production efficiency or the complex equipment required [2]. Until now, there is still a great demand for processing technologies that are suitable for manufacturing large-sized high-performance Mg alloys with relatively high efficiency at low cost.…”

A New Ultra-High-Strength AB83 Alloy by Combining Extrusion and Caliber Rolling

“…However, their commercial application is still very limited because of their poor mechanical performance and high processing cost compared with steel, Ti, and Al alloys [1]. Developing low-cost rare-earth free (RE-free) Mg alloys with high strength and good ductility is considered a prerequisite for their wider commercial adoption [1][2][3]. By incorporating grain refinement, precipitation hardening, and texture hardening, high strength has been achieved so far in Mg-Al- [4,5], Mg-Zn- [6][7][8], Mg-Ca- [9,10], and Mg-Sn- [11,12] based alloys.…”