Enhancement of Mechanical Properties and Rolling Formability in AZ91 Alloy by RD-ECAP Processing.

Qiong Xu,Aibin Ma,Bassiouny Saleh,Yuhua Li,Yuchun Yuan,Jinghua Jiang,Chaoying Ni

doi:10.3390/ma12213503

Qiong Xu, Aibin Ma + Show 5 more

Open Access

https://doi.org/10.3390/ma12213503

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Journal: Materials	Publication Date: Oct 25, 2019
Citations: 18	License type: CC BY 4.0

Affiliation: Hohai University, University of Delaware

Abstract

In this study, the influence of rotary-die equal channel angular pressing (RD-ECAP) processing on the mechanical properties and rolling formability of AZ91 alloys was investigated. The as-cast and pre-homogenized AZ91 alloys were pre-processed by RD-ECAP for 16 passes at 573 K and subjected to post-ECAP rolling at 573 K with a rolling speed of 10 m/min. The microstructure and deformation characteristics of the AZ91 alloys were characterized. Results demonstrated that fine-grained AZ91 alloys with improved strength and ductility were obtained via the high-pass RD-ECAP processing, indicating a good plastic formability. The ECAP-ed alloys were easily rolled at 573 K from 4.5 mm to 1.1 mm in thickness without edge cracking. After rolling, heterogeneous grain structures were observed with large numbers of twins and shear bands that created strong basal textures. The rolled AZ91 alloys exhibited higher tensile strength and appropriate elongation. The post-ECAP rolling was successfully used in the high productivity of AZ91 rolled plates with good mechanical properties.

Highlights

In recent years, Mg alloys have become appealing candidates for the electronics, automotive and aviation sectors as the lightest metallic material in structural applications [1,2,3]
322 MPa, respectively; the elongations (EL) increase to ~11.5% and ~19.6%, respectively. These results demonstrate that the as-homogenized alloy yields more excellent mechanical properties present results demonstrate that the as‐homogenized alloy yields more excellent mechanical than the as-cast alloy when subjected to rotary-die equal channel angular pressing (RD-equal channel angular pressing (ECAP)) processing in this work
Rolling, with improved edge cracks can be obtained by applying post-ECAP rolling on the ECAP-ed AZ91 i.e., C‐ECAP

Summary

Introduction

Mg alloys have become appealing candidates for the electronics, automotive and aviation sectors as the lightest metallic material in structural applications [1,2,3]. Due to the HCP structure and abundant dendritic second phases resulted from the high Al content, the formability and ductility of AZ91 alloys are poor [6,7,8]. Edge cracking occurs during rolling, and after rolling ductility is generally insufficient, causing the product quality and productivity to be significantly lowered. For this reason, high performance rolled AZ91 alloys with minimum material loss are important to be developed in order to precipitate industries

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