Effect of Reduction in Thickness and Rolling Conditions on Mechanical Properties and Microstructure of Rolled Mg-8Al-1Zn-1Ca Alloy

Yuta Fukuda,Masafumi Noda,Yasumasa Chino,Kazutaka Suzuki,Naobumi Saito,Tomomi Ito

doi:10.1155/2017/4065434

Abstract

A cast Mg-8Al-1Zn-1Ca magnesium alloy was multipass hot rolled at different sample and roll temperatures. The effect of the rolling conditions and reduction in thickness on the microstructure and mechanical properties was investigated. The optimal combination of the ultimate tensile strength, 351 MPa, yield strength, 304 MPa, and ductility, 12.2%, was obtained with the 3 mm thick Mg-8Al-1Zn-1Ca rolled sheet, which was produced with a roll temperature of 80°C and sample temperature of 430°C. This rolling process resulted in the formation of a bimodal structure in the α-Mg matrix, which consequently led to good ductility and high strength, exclusively by the hot rolling process. The 3 mm thick rolled sheet exhibited fine (mean grain size of 2.7 μm) and coarse grain regions (mean grain size of 13.6 μm) with area fractions of 29% and 71%, respectively. In summary, the balance between the strength and ductility was enhanced by the grain refinement of the α-Mg matrix and by controlling the frequency and orientation of the grains.

Highlights

A new approach for limiting environmental impact [1] while increasing the speed of a vehicle, by reducing its weight through the replacement of aluminum alloy with lightweight magnesium alloy, has attracted the attention of many researchers [2]
The elongation of the cast AZX811 alloy is as low as 2.3%, compared to the mechanical properties of the as-cast magnesium alloys [14, 17, 19] formed by other methods, as listed in Table 2, it is thought that the degree of elongation decreases and high values of the yield strength (YS) and ultimate tensile strength (UTS) are achieved because an intermetallic compound is formed when 1 mass% of calcium is added
The influence of the rolling rate, temperature, and intermediate heat treatment was investigated for the fabrication of metal plates with high strength and high ductility using incombustible cast AZX811 alloy as the starting material

Summary

Introduction

A new approach for limiting environmental impact [1] while increasing the speed of a vehicle, by reducing its weight through the replacement of aluminum alloy with lightweight magnesium alloy, has attracted the attention of many researchers [2]. Sakamoto et al reported that, by adding calcium to a magnesium alloy, the combustion temperature can be increased by more than 250∘C [3]. Improvements in the mechanical properties of the magnesium alloys have been achieved by adding different elements [4, 5], applying texture control during forging [6,7,8], and grain refinement [9]. In most of these studies, rolling [6,7,8,9]

Methods

Results

Conclusion