Microstructure characteristics and effect of aging process on the mechanical properties of squeeze-cast AZ91 alloy

Han, Guomin; Zhou, Han; Luo, Alan A.; Liu, B.C.

doi:10.1016/j.jallcom.2015.04.042

Cited by 28 publications

(9 citation statements)

References 42 publications

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“…This trend would lead to a loss of hardness. The CPs' precipitating during aging at 300 • C in the present work agrees with the previous results of AZ91 alloy investigations [8,33,41].…”

Section: = ( − )supporting

confidence: 92%

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Simulation and Prediction of the Vickers Hardness of AZ91 Magnesium Alloy Using Artificial Neural Network Model

et al. 2020

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In this study, an artificial neural network (ANN) model was used to simulate and predict the Vickers hardness of AZ91 magnesium alloy. The samples of AZ91 alloy were aged at different temperatures (Ta = 100 to 300 °C) for different durations (ta = 4 to 192 h) followed by water quenching at 25 °C. The age-hardening response of the samples was investigated by hardness measurements. The microstructure investigations showed that only discontinuous precipitates formed at low aging temperatures (100 and 150 °C), while continuous precipitates invaded all the samples at a high aging temperature (300 °C). Both discontinuous and continuous precipitates formed at the intermediate aging temperatures (200 and 250 °C). X-ray diffraction (XRD) analysis revealed that the microstructure comprised two phases: The α-Mg matrix and intermetallic β-Mg17Al12 phase. The alteration of the crystalline lattice parameters a, c, and c/a ratio with the aging time at various aging temperatures was also investigated. Both c and c/a ratio had the same behavior with aging time while a had an inverse trend. The observed variations of the lattice parameters were attributed to the mode of precipitation in AZ91 alloy. The ANN findings for the simulation and prediction perfectly conformed to the experimental data.

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“…This trend would lead to a loss of hardness. The CPs' precipitating during aging at 300 • C in the present work agrees with the previous results of AZ91 alloy investigations [8,33,41].…”

Section: = ( − )supporting

confidence: 92%

“…These calculated values of a and c are matched with recorded values in JCPDS card no. 65-3365 for Mg matrix, and they agreed well with the values reported in the literature[39,41]. The separation of aluminum to form β-Mg 17 Al 12 phase may be held responsible for the alteration in the lattice parameter values.…”

supporting

confidence: 89%

Simulation and Prediction of the Vickers Hardness of AZ91 Magnesium Alloy Using Artificial Neural Network Model

et al. 2020

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“…On the other hand, continuous precipitation was the most effective means of increasing mechanical resistance to this type of alloy [22]. During primary creep, the higher capacity of strain hardening for the pre-treated samples at all the loads was probably due to the continuous β-precipitates.…”

Section: Resultsmentioning

confidence: 99%

Strain Rate during Creep in High-Pressure Die-Cast AZ91 Magnesium Alloys at Intermediate Temperatures

et al. 2019

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During creep, magnesium alloys undergo microstructural changes due to temperature and stress. These alterations are associated with the evolution of the present phases at a microstructural level, creating different strain rates during primary and tertiary creep, and with the stability of the inter-metallic phase Mg17Al12 formed at these temperatures. In this paper, the results of creep testing of high-pressure die-cast AZ91 magnesium alloys are reported. During creep, continuous and discontinuous precipitates grow, which influences creep resistance. The creep mechanism that acts at these intermediate temperatures up to 150 °C is termed dislocation climbing. Finally, the influence of the type of precipitates on the creep behavior of alloys is determined by promoting the formation of continuous precipitates by a short heat treatment prior to creep testing.

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“…Compared with other metal materials, magnesium and its alloys have low density, high specific strength and stiffness, good thermal and electrical conductivity, excellent electromagnetic shielding ability, easy recycling, and many other advantages, which have a strong potential for use as structural materials in automotive, aerospace and 3C industries . A representative of the most important commercial magnesium alloys is the Mg–Al based alloy with the composition Mg–9Al–1Zn, known as AZ91, which has been studied a lot . Recently, people have paid more and more attention to magnesium alloys containing rare earth (RE) because of its high strength and good performance both at room and high temperatures .…”

Section: Introductionmentioning

confidence: 99%

“…A representative of the most important commercial magnesium alloys is the Mg–Al based alloy with the composition Mg–9Al–1Zn, known as AZ91, which has been studied a lot . Recently, people have paid more and more attention to magnesium alloys containing rare earth (RE) because of its high strength and good performance both at room and high temperatures . Mg–Gd alloy is one of the most promising alloys because of its excellent age hardening property and creep resistance up to 523 K .…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Effect of Cooling Rate on the Secondary Phase in As‐Cast Mg–Gd–Y–Zr Alloy

Wang

Xiao³

et al. 2017

Adv Eng Mater

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The effect of cooling rate on the composition, morphology, size, and volume fraction of the secondary phase in as-cast Mg-Gd-Y-Zr alloy is investigated. In the study, a casting containing five steps with thickness of 10-50 mm is produced, in which cooling rate ranging from 2.6 to 11.0 K s À1 is created. The secondary phase is characterized using optical microscope (OM), scanning electron microscope (SEM), and electron probe micro-analyzer (EPMA). The volume fraction of the secondary phase is determined using OM and quantitative metallographic analysis, and Vickers hardness test is conducted to verify the analysis results. The effect of the cooling rate on the volume fraction of the secondary phase is discussed in detail. The result shows that with the increase of the cooling rate, the size of the secondary phase decreases. The effect of the cooling rate on the volume fraction of the secondary phase is complicated somewhat. A comprehensive analysis on the experimental data shows that a critical cooling rate may exist, over which the volume fraction of the secondary phase decreases with the increase of the cooling rate, however under which the volume fraction increases with the increase of the cooling rate.

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Microstructure characteristics and effect of aging process on the mechanical properties of squeeze-cast AZ91 alloy

Cited by 28 publications

References 42 publications

Simulation and Prediction of the Vickers Hardness of AZ91 Magnesium Alloy Using Artificial Neural Network Model

Simulation and Prediction of the Vickers Hardness of AZ91 Magnesium Alloy Using Artificial Neural Network Model

Strain Rate during Creep in High-Pressure Die-Cast AZ91 Magnesium Alloys at Intermediate Temperatures

Experimental Study on the Effect of Cooling Rate on the Secondary Phase in As‐Cast Mg–Gd–Y–Zr Alloy

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