Papers by Keyword: AZ80

Abstract: In recent years, the weight reduction of components in the automotive and aircraft industries has become a major issue in achieving sustainable development goals (SDGs), as it is critical to reducing fuel and energy consumption. Magnesium (Mg) alloys have the lowest density among all practical metals and have attracted attention as lightweight materials. For weight reduction, rims and wheels are fabricated by the hot forging of Mg alloys, and the shortening of the die life is a problem because of the high load on the die and the tendency to burn and wear caused by adhesion in the hot forging of Mg. The T-shape compression test (TSCT) can evaluate friction in complex deformations involving both extrusion and compression and can achieve a surface area enlargement greater than 50%. In this study, a hot V-groove friction test based on the TSCT is proposed as a friction test that simulates hot extrusion and forging. The friction coefficient is identified from the aspect ratio of the product after compression, as either longitudinal extrusion or transverse compression is the preferred deformation due to the effects of friction. The proposed test combines extrusion and compression deformation, has a high surface area expansion ratio of a greater than 50%, and produces a two-dimensional deformation in which the circle collapses. In addition, the dimensions and compression ratio can be easily changed. In this study, as part of the development of a V-groove friction test, we examine the tool dimensions and mechanism of adhesion under different temperatures and compression ratios. Using the AZ80 alloy as experimental material and varying the temperature and stroke amount, we investigate the effects of the working temperature on adhesion growth during hot forming.

Abstract: Formability of two magnesium alloys, namely, AZ80 and ZE10, has been investigated. Both alloys were supplied with a thickness of 0.8 mm. The grain structure of the as-received AZ80 alloy showed dislocations, twins and second-phase particles and-/or precipitates distributed uniformly within grains. These were not obvious on the ZE10 alloy. The investigations were carried out at room temperature for both alloys in the as-received and heat treated conditions (410^oC for 1 hour followed by water quench). The heat treatment significantly changed the grain structure of the AZ80 alloy, but did not affect the ZE10 alloy apart from grain enlargement. The formability was studied on the basis of plastic strain ratio (r) and strain hardening coefficient (n) by means of tensile testing. In the as-received condition, the ZE10 alloy had a slightly better formability () than AZ80 alloy. Following heat treatment, however, the formability of the AZ80 alloy was improved significantly (by about 26%), while the ZE10 alloy did not show any significant change.

Abstract: Automobile wheel hub of Mg alloy with single-step extrusion-forging process was developed, and the microstructure and mechanical properties after heat treatment were investigated. The forged hubs have a hub wall of as thin as 3mm, and 4-7kg lighter than that of Al alloy wheel hub with a same size and design of each wheel hub, that would lead remarkable reduction of fuel consumption. The tensile strength larger than 308 MPa, good corrosion fatigue and impacting resistance sampled from the hubs obtained.

Abstract: Thermal Deformation Property and Constitutive Model of AZ80 Magnesium Alloy had been studied with thermal simulation experiment. Dynamic recrystallization for AZ80 magnesium alloy had occurred under different strain rate at 583K(310°C). Dynamic recrystallization had occurred more completely and the grain size was reducing with increasing of strain rate. Dynamic recrystallization had occurred more completely and the grain size was reducing with increasing of strain rate. According the Arrhenius equation, a kind of constitutive equation of AZ80 Magnesium alloy which considered the strain had been put forward, and the relative errors between calculation results by the stress-strain model and experiment results are less than 10.5%.

Abstract: It is obviously different mechanical properties of the rolled magnesium alloy plate when stretched along different directions at room temperature. In this study, three groups of samples for uniaxial tension were cut from the as-rolled AZ80 plate with their tension directions either at 0°, 45°or 90°to the rolled direction (RD) of the sheet. Results show that the ductility of the 45°samples was significantly better than that of 0°and 90°samples. The electron backscatter diffraction (EBSD) technique was used to investigate the microstructure and textures evolution. Along with the increase of deformation, more low-angle grain boundaries arise in the 0°and 45°samples than the 90°samples. At the same time, the texture components that {10-10} prismatic plane perpendicular to the tension direction were significantly enhanced in three groups of samples.

Abstract: Grain refinements during hot compression of continuous casting AZ80 alloy bars and extrusive AZ61, AZ80 alloy bars were observed. The hot compression true stress-true strain curves of extrusive AZ61 and AZ80 alloy had similar tendencies, which were that the true stress increased and had a peak around 0.2 true strain, and then the stress decreased and was almost even from about 0.4 true strain. The stress peaks shifted to the high strain side as the compression speed, true strain speed, increased. However, the stress peaks did not shift at different compression temperatures. Fine grains were obtained under the condition of high strain speed and low temperature, but the grain sizes were uneven at low temperature compression. The stress peaks in the hot compression true stress-true strain curves of continuous casting AZ80 did not shift at different compression temperatures. AZ80 forging products with fine grains are expected to be formed under various conditions by using continuous casting AZ80.

Abstract: The curves of true stress-strain of AZ80 Magnesium alloy had been tested with thermal simulation experiment, at the conditions of the experimental temperature being 260°C~ 410°C, and strain-rate being 0.001~ 10s-1, and the deformation degree being 50％. According the Arrhenius equation, a kind of constitutive equation of AZ80 Magnesium alloy which considered the strain had been put forward, and the relative errors between calculation results by the stress-strain model and experiment results are less than 10.5%.

Abstract: First results of the influence of Equal Channel Angular Pressing (ECAP) on the wear behavior of the magnesium alloy AZ80 have been discussed. The evident grain refinement and redistribution of second phases in the 4 pass processed materials resulted in an increase of the hardness state in the AZ80 alloy. Wear tests conducted on a pin-on-disc set-up revealed better wear resistance for the 4 pass processed materials. Isothermal aging treatment, at 210°C for 10 hrs, of the ECAP processed materials showed that wear resistance properties are improved markedly. For incremental sliding speeds during the wear test, wear rate of the AZ80 alloy was found to increase.

Abstract: The mechanical properties and microstructures were investigated for AZ80 Mg alloy during plane strain compression and extrusion processing. The results show the tensile strength increases with the increasing deformation degree in the two-phase zone due to sufficient dynamic recrystallization and work-hardening effect. In single-phase zone, the tensile strength increases firstly and then does not varies basically when the deformation degree is greater than a certain critical value. This is very beneficial to optimize processing parameters to obtain microstructure with improved mechanical behavior.

Abstract: Finite element simulation of the effects of mould angle and friction condition on the equal channel angular pressing (ECAP) for AZ80 magnesium alloy were investigated by using DEFORM-3D program. The results show that the curve of load-displacement was divided into several stages including rapid increasing stage, load fluctuation, rapid increasing stage, steady stage and rapid drop stage. Firstly, when the angle decreased from 150°to 90°, the maximum load increased, and the same as energy consuming. In addition, the average effective strain increased with the decreasing of mould angle after single extrusion, while the degree of effective strain uniformity of the sample decreased and keep greater strain grads between inner and surface part. Secondly, the work load ascended with the increasing of the friction coefficient from 0 to 0.3, and one part of load overcome the friction and the other part is used for deformation of the sample. With the increment of friction coefficient, the average effective strain keeps steady value, while the degree of effective strain uniformity of the sample decreased. As mentioned above, large angle mould and low coefficient of friction should be adopted during ECAP deformation for AZ80 magnesium alloy.