H. Chang

Microstructure and Properties of Pure Mg/ZK60 Laminate Processed by Accumulative Roll Bonding

Commercial pure magnesium with excellent damping capacity and ZK60 magnesium alloy with high strength were accumulative roll bonded (ARBed) at 300oC up to 3 cycles to fabricate Mg laminate consisting of alternating layers of pure Mg and ZK60. Microstructure, tensile properties and damping capacity of the sheets were analyzed. The research suggests that Mg sheet having both high strength and excellent damping capacity can be developed by accumulative roll bonding of pure Mg and ZK60 Mg alloy.

Texture development of ARB processed Mg/Al multilayers

Our work deals with accumulative roll bonding (ARB) of pure Mg sheet (0.9mm thickness) and of Al5052 sheet (0.5mm). A stacking of Al-Mg-Al was firstly rolled to 50% reduction at 400°C and secondly ARB has been processed up to 3 cycles. In such multilayers as well as highly mixed composites of two-phased system texture development, phase reactions and strain accumulation are of basic interest, which needs a combination of different experimental methods for characterization. The present paper deals with the global texture evolution measured by thermal neutrons to average always over the whole sample thickness, SEM and optical microscopy indicates the macroscopic development of Mg and Al layers. The initial materials show typical and strong basal plane texture of hexagonal Mg (17.9mrd) and a recrystallization texture of cubic Al (8.5mrd). Co-deformation of Al/Mg/Al leads to strong decrease of both textures, whereas Mg has always a much stronger texture than Al5052. ARB processing produces only weak Al-textures. After sandwich-rolling and 1 cycle ARB rotated cube is observed in Al5052, which does not exist after 2 and 3 cycles of ARB.

Texture Gradient in a Single Pass ECAPed Pure Mg by Neutron Radiation

Single pass ECAP of pure Magnesium was performed and stopped after 50 % deformation; textures thereafter at the ingoing, the deformation and the outgoing channel were characterized by neutron radiation and related to the deformation mode. A gradient texture evolution was obtained, which was attributed to the inhomogeneous distribution of the effective stress and strain, and also the inevitable existence of friction.

Effect of texture on damping behaviour in an AZ80 alloy

An extruded AZ80 Mg alloy was utilized to investigate the texture effect on the damping behavior. Results showed that different input textures had great effect on the damping behaviour by strain-depended test, but did not showed strong influence on the temperature-depended behaviour which has been discussed.

Effect of ECAP on the Microstructure and Tensile Property of SiCp/AZ91 Magnesium Matrix Composite

Magnesium matrix composite reinforced with SiC particle was fabricated by compocasting method. The SiCp/AZ91 composite was extruded initially, then subjected to ECAP. The microstructure and tensile properties of the composite at ambient and elevated temperature were investigated. After ECAP, the matrix alloy was significantly refined due to the dynamic recrystallization occurred during ECAP. Both the ambient yield stress and ultimate tensile stress of SiCp/AZ91 were increased after 1-pass and 2-pass ECAP and decreased after 4-pass ECAP. The ECAP processed composite exhibited superplasticity at elevated temperature, which is mainly due to the grain refinement of matrix alloy. The dominant deformation mechanism of the ECAPed composite at high temperature was grain boundary sliding. However, the sliding was prohibited due to the present of SiC particle.