Title

Influence of Extrusion Temperature on Microstructure and Mechanical Behavior of Duplex Mg-Li-Al-Sr Alloy

Abstract

In this study, as-cast alloy Mg-9Li-3Al-2.5Sr (LAJ932) ingots were extruded at different temperatures using an extrusion ratio of 28, and the underlying microstructural evolution and mechanical behavior were investigated. The results show that grains in the extruded LAJ932 alloy are much finer than those in the as-cast one, which indicates that the microstructural evolution during extrusion is governed by dynamic recrystallization. With increasing extrusion temperature, the grain size of the extruded alloy increases, and the strength decreases whereas the elongation increases. The alloy extruded at 250 °C possesses the highest strength of 238 MPa with an elongation of 18.1%, whereas1 the alloy extruded at 350 °C has the largest elongation of 21.6% with a strength of 208 MPa. The differences in microstructure characteristics between the α-Mg phase and ß-Li phase in the alloy extruded at 250 °C suggest that continuous dynamic recrystallization (CDRX) occurs in the α-Mg phase during extrusion whereas the microstructure evolution in ß-Li phase is governed by discontinuous dynamic recrystallization (DDRX). DDRX occurs in α-Mg phase to some extent and the fraction of DDRX grains in the alloys increases with increasing extrusion temperature.

Department(s)

Materials Science and Engineering

Comments

The authors would like to acknowledge financial support by the National Natural Science Foundation (Project No. 51601024 ), the National Key Research and Development Program of China (Project No. 2016YFB0700403 & Project No. 2016YFB0301100 ), the Chongqing Research Program of Basic Research and Frontier Technology (Project No. cstc2016jcyjA0418 ), the Fundamental Research Funds for the Central Universities (Project No. 106112016CDJXZ138811 ) and the support of the 111 Project (Project No. B16007 ) by the Ministry of Education and the State Administration of Foreign Experts Affairs of China.

Keywords and Phrases

Dynamic Recrystallization; Extrusion Temperature; Mechanical Properties; Mg-Li Alloy; Microstructure

International Standard Serial Number (ISSN)

0925-8388

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2018 Elsevier Ltd, All rights reserved.

Share

 
COinS