Microstructure and Mechanical Properties of Mg/Al Clad Bars with Ni Interlayer Processed by Compound Castings and Multi-Pass Caliber Rolling

Lu Chen,Ying Fu,Chunyong Liang,Ning Liu,Fuxing Yin

doi:10.3390/met8090704

Abstract

Magnesium/aluminium clad bars were fabricated by compound casting and multi-pass warm caliber rolling. A Ni interlayer prepared using a plasma spraying process was inserted between the parent metals to improve the interfacial characteristics during the casting process, and the effect of caliber rolling on the evolution of the interfacial microstructure and mechanical properties of the Mg/Ni/Al composites was investigated. The results show that the formation of Mg-Al intermetallic phases was impeded effectively by the Ni interlayer and a typical AZ31/Ni/6061 multilayer structure with metallurgical bonding was formed during the compound casting process. In addition, an inhomogeneous strain distribution in the AZ31 and 6061 alloys were characterized during the rolling process. The AZ31 clad layer accommodated a larger proportion of the plastic strain during the initial passes, while the strain in the Mg core layer increased with increasing number of passes. The Ni interlayer fragmented during the rolling process, and transformed into the dispersed particles at the interface. Meanwhile, the fresh AZ31 and 6061 base alloys squeezed out and bonded together under the rolling force, and a well-bonded interface with no visible defects was formed.

Highlights

The fast development of modern industries has resulted in the increasing use of lightweight materials in many fields
Clad materials consisting of magnesium and aluminium alloys may be the most effective approach to combine some advantages of the constituent materials that cannot be fully supplied by monolithic materials, and to extend their applications [1,2,3]
The AZ31/6061 clad bars were prepared by compound casting process with the Ni interlayer and were multi-pass warm caliber rolled

Summary

Introduction

The fast development of modern industries has resulted in the increasing use of lightweight materials in many fields. Magnesium and aluminium alloys are widely employed. The former exhibits low density, high specific strength, and high stiffness, and the latter has good plasticity and excellent corrosion resistance. Various bonding methods have been used to prepare Mg/Al bimetallic composites, including accumulative roll bonding [4], hot co-extruding [5], diffusion bonding [6], friction stir welding [7], explosive cladding [8], high-pressure torsion [9], and compound casting. The compound casting process can produce excellent metallurgical bonding between dissimilar alloys at a low cost and a simple production procedure [10,11]. The formation of brittle, hard Mg-Al intermetallic compounds in the bonding interface causes an inherent

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Discussion

Conclusion