Behavior Of Magnesium Alloy Research Articles

High Cycle Fatigue Behavior of Magnesium Alloys under Corrosive Environment

The high cycle fatigue characteristics of magnesium alloys under low humidity, high humidity (80% RH) and sprayed 5%NaCl solution environments have been introduced. Fatigue limit of bulk magnesium alloy was significantly reduced even under high humidity condition, while other structural materials such as steel and aluminum alloy showed no influence of humidity on fatigue limit. The reduction of fatigue limit under 5% NaCl environments was much larger than that under high humidity environment. The remarkable reduction of fatigue limit under corrosive environments was attributed to the formation of corrosion pit, which was induced by simultaneous action of mechanical loading and corrosive environment. To improve the reduced fatigue strength under corrosive environment, coating used to apply on the surface. Non-chromium chemical conversion coating showed superior effect on the improvement of fatigue strength under corrosive environment compared to anodized coating. Fatigue strengths of the coated and painted AZ61 alloy under high humidity and 5%NaCl environments showed almost the same fatigue strength as bulk material under low humidity.

Experimental and Numerical Study of Cyclic Creep of Cast Magnesium Alloy at High Temperature

The cast magnesium alloys as AM50 offer a good strength, ductility and surface finish for automotive industry. But the poor creep resistance limited its application to power components such as engine and transmission cases at temperatures in excess of 100°C. In order to investigate the cyclic creep behavior of Magnesium Alloy at high temperature, creep tests of plate specimens AM50 were conducted in this work. Based on the analysis about the microstructure and defects of AM50 under the condition of cyclic creep, a cyclic creep constitutive model with isotropic and scalar damage parameter was developed. Furthermore, the proposed model was experimentally verified by analyzing the cyclic creep and recovery response of Cast Magnesium alloy under cyclic loading with dwell time. Comparisons between calculated results and experimental data showed good agreement.

恒温クロス圧延により微細化されたAZ91マグネシウム合金板材の超塑性挙動

恒温クロス圧延により微細化されたAZ91マグネシウム合金板材の超塑性挙動

Acoustic Emission Investigation of the Anelastic Recovery Behavior of Basal Plane Textured AZ31B as a Function of Loading Direction

In order to study the texture effects on the anelastic recovery behavior of magnesium alloy, basal plane textured AZ31B alloy was compressed parallel and vertical to the extrusion direction. AE measurement was applied to characterize the deformation and the anelastic recovery behaviors. A model for the correlation between applied strain and the cumulative AE counts in detwinning was proposed. The effects of loading direction to the deformation and twinning behavior were discussed.

Mechanical Properties and Damping Behavior of Magnesium Alloys Processed by Equal Channel Angular Pressing

Equal channel angular pressing (ECAP) was applied to commercial pure magnesium alloy, Mg-1wt%Si alloy and Mg-4.2wt%Zn-0.7wt%Y alloy. With increasing ECAP passes, both tensile strength and ductility of the alloys are increased, which are mainly resulted from the grain refinement. At the same time, for the Mg-Zn-Y alloy with inherent low damping capacity, damping capacity is increased after ECAP passes, however, the damping capacity is still low even after 6-pass ECAP. While for the commercial pure magnesium and Mg-Si alloy with inherent high damping capacity, although the damping capacity is decreased obviously after ECAP, Q-1 is still greater than 0.01. The damping capacity after ECAP processing is mainly influenced by grain size and deformation microstructure. ECAP paves a way for the development of magnesium alloys with high strength and high ductility combined with high damping capacity.

RETRACTED: Electrochemical behaviour of magnesium alloys strained in aqueous solutions

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RETRACTED: Mechanoelectrochemical behavior of magnesium alloys

This article has been retracted at the request of the Chief Editors and authors. Please see http://www.elsevier.com/locate/withdrawalpolicy . Reason: Not all identified co-authors were aware of, or approved of the publication of this article. The Editors and Publisher would like to reaffirm their commitment to providing content of the highest scientific value and will strive to avoid such instances in the future.

Effect of LaCl3 on the Structure and Properties of Magnesium Alloys

By use of the Zwick electronic universal material testing machine, X-ray diffractometer, SEM, EDX, image analyzer and corrosion test, the effects of LaCl3 on the mechanical properties, structure, fractography and corrosion behavior of magnesium alloy have been studied. The results show that minute nodular Al10La2Mn7 phases can be formed in Mg melts after fluxes containing LaCl3 are added to Mg melt. The Al10La2Mn7 phases can act as the nucleating site of γ phases, and the γ phases can be refined. With the flux containing 5% LaCl3, the σb and δ of the Mg alloy can be improved from 161MPa and 2.1% to 203MPa and 4.0% by 26% and 100%, respectively. The corrosion rate of magnesium alloys can decrease from 1.10 mg/(cm2.d) to 0.17 mg/(cm2.d) by 84% with the use of flux containing 5% LaCl3. Rare earth (RE) elements are often added to the magnesium alloy to improve the alloy structure and the room or elevated temperature mechanical properties. But up to present, the RE elements added to Mg melt is often in the form of pure RE alloy or RE master alloy [1]. Because RE is the oxidizable material, this kind of adding process often leads to low RE utilization ratio and high use-cost. Besides, this process can easily induce segregation of RE and the appeared coarse RE phases will lower the Mg alloy mechanical properties. By far, there is few research reports about RE contained compound added to Mg alloy melt. In this paper, the effects of Lanthanum chloride (LaCl3) on the structure and mechanical properties of Mg alloy are studied for the first time. The aim is to explore a new way to improve the Mg alloy properties.

Microstructure, Texture and Deformation Behavior of Lithium Containing Magnesium Alloys

In the present work the deformation behavior of magnesium alloys with different lithium content has been investigated in terms of microstructures, crystal parameters, textures and mechanical properties. The lattice constants of a phase (hcp) determined by XRD varied with its lithium content and at the same time there are some changes in the texture composition. The plasticity would remarkably increase while b phase (bcc) becomes dominant in the microstructure of alloys.

恒温圧延により微細化されたAZ91Dマグネシウム合金板材の超塑性挙動における異方性

恒温圧延により微細化されたAZ91Dマグネシウム合金板材の超塑性挙動における異方性

A Study on Dynamic Fracture Behavior of Magnesium Alloys under Biaxial Stress

In this study, dynamic behavior of the crack under dynamic biaxial stress was investigated concerning of these situations. Specimen shape was assumed to be a biaxial fracture, and the load device was with a hydraulic high-speed biaxial experiment device, which this laboratory had developed. Dynamic stress intensity factors and strain behaviors in the crack tip, angle of the pre-crack and crack propagation direction, and relate about the dynamic fracture toughness value under a dynamic biaxial stress was studied.

Superplastic Behavior of Magnesium Alloy Processed by ECAE

An AZ91 magnesium alloy with a very small grain size of less than 1 μm was processed by equal channel angular extrusion (ECAE). The alloy showed a large elongation of 661 % at a low temperature of 473 K, which is 0.5 T m . Grain boundaries of the alloy were in a non-equilibrium state.

AE behaviors evaluation with bp neural network

This paper reports our experiment on training a three layer forwards neural network with backpropagation algorithm (BP) to memorise acoustic emission (AE) behaviors of magnesium alloy during fatigue test process and perform the mapping from AE behaviors to fatigue crack propagation. This study reveals the potential possibility of using artificial neural networks for automated AE testing. Simulation results are very encouraging and conclusively in favor of this attempt.