Current development of creep-resistant magnesium cast alloys: A review

Mo, Ning; Tan, Qiyang; Bermingham, Michael; Huang, Yuanding; Dieringa, Hajo; Hort, Norbert; Zhang, Mingxing

doi:10.1016/j.matdes.2018.06.032

Cited by 169 publications

(39 citation statements)

References 144 publications

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“…Despite these merits, magnesium and its alloys have poor abrasion and corrosion resistance, and like any hexagonal-close packed (HCP) metal, magnesium displays notoriously strong anisotropic mechanical properties of limited strength and poor ductility at room temperature which greatly hinders the metal's potential applications [4,5]. Along these, the greatest drawback that limits Mg and its alloys from the broader application in the automotive and aerospace industries is low creep resistance at elevated temperatures, i.e., above 175 °C , since some critical components operate at and above this temperature [6]. This drawback is attributed to the limited number of slip systems (HCP structure), which makes the metal brittle and susceptible to creep damage [7].…”

Section: Introductionmentioning

confidence: 99%

Indentation-based characterization of creep and hardness behavior of magnesium carbon nanotube nanocomposites at room temperature

Thornby

Verma²,

Mullis

et al. 2019

SN Appl. Sci.

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The time-dependent plastic deformation response of magnesium/carbon nanotube (CNT) nanocomposites containing 0.25, 0.5, and 0.75 vol% of carbon nanotubes is investigated through depth nanoindentation tests against monolithic pure magnesium in the present study. The Mg-CNT nanocomposite materials were successfully synthesized via a powder metallurgy technique coupled with microwave sintering followed by hot extrusion to produce 8-mm diameter, long solid bars. All depth-sensing indentation creep tests were conducted at ambient (room) temperature employing a diamond Berkovich pyramidal indenter. These tests are dual-stage, i.e., loading to a prescribed peak load of 50 mN, holding the peak load constant for a dwell period of 500 s, and finally unloading. Various strain rates of 0.01, 0.1, 1, and 10 s −1 were performed to assess the effects of strain rate and dwell time on the ambient temperature creep response of the Mg-CNT nanocomposites. The outcomes of these tests are explained through material hardness, microstructure, the extent of CNT content in each material, and strain rate sensitivity. Upon analyzing the nanoindentation creep tests, the dominant creep mechanism at room temperature was found to be a dislocation creep mechanism. It is also found that CNTs increase the creep resistance of magnesium. Findings of this study can be used as a starting point for a high-temperature creep study on Mg-CNT nanocomposites. This paper is a continued study from our group on time-dependent plastic deformation of Mg nanocomposites (i.e., see Haghshenas et al., Journal of Composite Materials,

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Section: Introductionmentioning

confidence: 99%

Indentation-based characterization of creep and hardness behavior of magnesium carbon nanotube nanocomposites at room temperature

Thornby

Verma²,

Mullis

et al. 2019

SN Appl. Sci.

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“…when the creep stress exponent n = 2-3, the corresponding main creep mechanism is the grain boundary slip and when the creep stress exponent n = 3-7, the corresponding main creep mechanism is the dislocation creep, which generally occurs under low temperature and high stress It could be seen that creep stress exponent n increased slightly with creep test temperature increasing. In general, when creep stress exponent n = 1, the creep behavior of the Mg alloy is considered to be mainly affected by diffusion, which generally occurs under conditions of higher temperature and lower stress, including Coble creep (grain boundary diffusion) and N-H creep; when the creep stress exponent n = 2-3, the corresponding main creep mechanism is the grain boundary slip and when the creep stress exponent n = 3-7, the corresponding main creep mechanism is the dislocation creep, which generally occurs under low temperature and high stress conditions [20,[29][30][31]. In this paper, the creep stress exponent n was 3.0 and 3.3 at a temperature of 125 • C and 150 • C respectively, under a stress of 40-100 MPa.…”

Section: Tensile Creep Characteristicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Lots of researches on creep characteristics of as-cast Mg-Al based alloys were carried out [5,20,21], while few researches focused on wrought Mg-Al based alloys. According to former research [20], dislocation climbing and grain boundary sliding were the dominant creep mechanisms for as-cast Mg-Al based alloys. The further addition of Si, rare earth elements or alkaline earth elements could enhance creep resistance of as-cast Mg-Al based alloys, which was attributed to heat-resistant intermetallic particles hindering grain boundaries sliding and dislocation slip, or to strengthening Mg matrix via solid solution and/or precipitation hardening [20].…”

Section: Introductionmentioning

confidence: 99%

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Microstructures, Tensile Properties and Creep Characteristics of as-Extruded AZ91 Magnesium Alloy Containing Si, Ca and Rare Earth Elements

Wu¹,

Cheng

Zheng

et al. 2019

Metals

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Wrought AZ (Mg-Al-Zn) series alloys have attracted lots of researches, due to low cost, high strength and good formability. Few researches focus on creep characteristics of wrought AZ series alloys, which might be of significance to extensive use of low-cost wrought Mg-Al based alloy at elevated temperature. The microstructures, tensile properties and creep characteristics of as-extruded Mg-9Al-Zn-0.5RE-0.5Ca-0.5Si (wt.%, named AZXSE91000) alloy were investigated by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometer (XRD), TEM (transmission electron microscopy), tensile tests and tensile creep tests (40-100 MPa, 125-150 • C). The as-extruded AZXSE91000 alloy exhibited good tensile strength both at room temperature and elevated temperature. The co-addition of Si, Ca and rare earth elements can improve the heat resistance of as-extruded AZ91 alloy resulting from fragmented heat-resistant particles hindering grain boundaries sliding. The steady creep rates of as-extruded AZXSE91000 alloy can be comparable with that of as-cast AZ91 alloy under similar experimental conditions. Dislocation climbing and grain boundary slip should dominantly contribute to the creep of as-extruded AZXSE91000 alloy. The asymmetric discontinuous precipitation in crept samples revealed that diffusion played an unneglected role during the creep process.

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“…Magnesium (Mg) alloys have received extensive attention in industrial applications due to their low density, low modulus of elasticity, high‐specific strength, and high‐specific stiffness. [ 1–4 ] However, the low‐temperature formability [ 5 ] and low corrosion resistance [ 6–8 ] of Mg alloys limit their large‐scale applications.…”

Section: Introductionmentioning

confidence: 99%

Effect of Steels on the Purity of Molten Mg Alloys

et al. 2020

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Magnesium (Mg) alloys have received extensive attention in industrial applications due to their low density, low modulus of elasticity, high-specific strength, and high-specific stiffness. [1-4] However, the low-temperature formability [5] and low corrosion resistance [6-8] of Mg alloys limit their large-scale applications. Many researches have indicated that the impurity elements, Fe, Ni, Cu, Co, in Mg alloys can strongly increase their corrosion rate, [9-11] and also severely deteriorate the mechanical [12-14] and damping properties. [15] When the impurities content in alloys exceeds the "tolerance limit" (10 ppm magnitude), the corrosion rate of Mg alloys will be exponentially accelerated. [16] Therefore, it is of great significance to strictly control the purity of the Mg alloys, especially the purity of the molten alloys before casting. Unfortunately, it is almost impossible to completely avoid these impurities during the production of Mg alloys. First, during Mg-metal smelting, no matter whether the Pidgeon method or the electrolytic magnesium method is used, there are always some impurities picked up from the raw materials. Second, these elements existing in the steel tools and steel crucibles can be dissolved in the molten Mg alloys during the melting process. [17-20] The purification of the molten Mg and Mg alloys has been studied extensively. [21-24] However, the effect resulting from defined tools on the Mg alloys production is rarely studied. [19,25] Scharf and Ditze [19] studied the interaction layers between AZ91 and AS31 with steel crucibles. The dissolution of iron, lowcarbon steel, and SUS316 (11wt% Ni, 17wt% Cr, remainder Fe) crucibles in commercial pure molten Mg was investigated by Taninouchi et al. [25] However, the influence of the types of used steels on the purity of molten Mg alloys has not been studied. Only by understanding the specific impact of elements coming from the tooling materials on the purity of molten Mg alloys can assure the purity of Mg alloys. This work aims to quantitatively determine the effect of tooling materials on the purity of Mg alloys melt. The most commonly cast Mg alloys, AZ91D, and AM50A, were studied. Three types of common tooling materials used in the production of Mg alloys: 20# steel, H13 steel, High-CrNi (022Cr25Ni7Mo4N) steel, were studied. Low carbon steel (here 20#) is the most common material used as the crucible materials for the Mg alloys synthesis. H13 steel is commonly used for Mg alloys casting molds. High-CrNi heat-resistant steel is commonly seen for the reduction tank in the Pidgeon process. The interactions between these tooling materials and Mg alloys were pre-evaluated using the Thermo-Calc 2019 software [26] based on the TCMG5 thermodynamic database. The influence of tooling materials on the purity of molten Mg alloys was experimentally studied using the liquid-solid diffusion method. What is more, the thermodynamic information is very important for the effective alloy design as well as the prediction of the distribution of impurities in al...

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Current development of creep-resistant magnesium cast alloys: A review

Cited by 169 publications

References 144 publications

Indentation-based characterization of creep and hardness behavior of magnesium carbon nanotube nanocomposites at room temperature

Indentation-based characterization of creep and hardness behavior of magnesium carbon nanotube nanocomposites at room temperature

Microstructures, Tensile Properties and Creep Characteristics of as-Extruded AZ91 Magnesium Alloy Containing Si, Ca and Rare Earth Elements

Effect of Steels on the Purity of Molten Mg Alloys

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