Exceptional grain refinement in a Mg alloy during high pressure torsion due to rare earth containing nanosized precipitates

Sun, Wanting; Qiao, Xiao Guang; Zheng, M.Y.; He, Yang; Hu, Nan; Xu, Chao; Gao, Nong; Starink, M.J.

doi:10.1016/j.msea.2018.05.021

Cited by 61 publications

(15 citation statements)

References 53 publications

(52 reference statements)

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“…The saturation (or maximum) hardness values for different magnesium alloys are summarized in Table with the minimum grain sizes reported. The hardness saturation in commercial alloys are typically in the range of ≈110–130 kgf mm −2 but slightly larger hardness values are observed in alloys with a high content of rare earth elements . The evolution of hardness in Mg alloys with a high content of alloying elements may be affected by previous thermal treatments .…”

Section: Mechanical Propertiesmentioning

confidence: 99%

“…The hardness saturation in commercial alloys are typically in the range of ≈110–130 kgf mm −2 but slightly larger hardness values are observed in alloys with a high content of rare earth elements . The evolution of hardness in Mg alloys with a high content of alloying elements may be affected by previous thermal treatments . Supersaturated alloys can also exhibit a further increase in hardness due to an ageing treatment post‐HPT as observed in the WE43, Mg‐8% Gd‐3% Y‐0.4% Zr, and Mg‐8.2% Gd‐3.8% Y‐1.0% Zn‐0.4% Zr alloys.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

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Processing Magnesium and Its Alloys by High‐Pressure Torsion: An Overview

Figueiredo

Langdon

2018

Adv Eng Mater

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Magnesium and its alloys have attracted significant attention in recent years because they display high strength-to-density ratios, they are biodegradable and they provide a potential for hydrogen storage. Many investigations have examined the effect of high-pressure torsion processing on the microstructures and properties of these materials so that numerous reports are now available. This overview provides a summary of the observations reported to date on the structure and mechanical property evolution including the nature of grain refinement, the grain boundary misorientation distributions, texture evolution, and the minimum grain size. For convenience, the mechanical properties are separated into hardness, tensile behavior, and superplastic properties. It is shown that the mechanism of grain refinement differs from other metallic materials processed by severe plastic deformation but high strength may be achieved in magnesium alloys and exceptional ductility in pure magnesium. Hydrogen storage and corrosion behavior are also examined together with a discussion of recent attempts to produce magnesium-based nanocomposites through processing by high-pressure torsion.

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Section: Mechanical Propertiesmentioning

confidence: 99%

Section: Mechanical Propertiesmentioning

confidence: 99%

Processing Magnesium and Its Alloys by High‐Pressure Torsion: An Overview

Figueiredo

Langdon

2018

Adv Eng Mater

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“…Therefore, one of the most direct methods to improve strength and ductility simultaneously is to produce an UFG microstructure. The development of UFG microstructures is generally along two distinctive directions: breaking down the pre-existing microstructure by severe plastic deformation (SPD) [ 30 , 31 , 32 , 37 , 38 ], and/or introducing nano-scaled precipitates by heterogeneous nucleation [ 14 ]. The previous one has successfully been applied in many HCP materials.…”

Section: Resultsmentioning

confidence: 99%

“…Submicrometer- or nano-scale ultrafine grained (UFG) materials have been investigated extensively in recent years owing to their new physical properties and excellent mechancial properties [ 27 , 28 ]. Various severe plastic deformation (SPD) techniques have been applied to acquire UFG microstructures, such as equal-channel angular pressing (ECAP) [ 29 , 30 ] and high-pressure torsion (HPT) [ 31 , 32 ]. However, considering the high deformation resistance during the deformation process and heterogeneous deformation domain (such as shear bands [ 33 ]), these SPD approaches are hardly applied in near β-Ti alloys.…”

Section: Introductionmentioning

confidence: 99%

Strengthening of a Near β-Ti Alloy through β Grain Refinement and Stress-Induced α Precipitation

Chen

Feng³

et al. 2020

Materials

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Near β-Ti alloys with high strength and good ductility are desirable for application in aviation and aerospace industries. Nevertheless, strength and ductility are usually mutually exclusive in structural materials. Here we report a new thermo-mechanical process, that is, the alloy was cross-rolled in β field then aged at 600 °C for 1 h. By such a process, a high strength (ultimate tensile strength: 1480 MPa) and acceptable ductility (elongation: 10%) can be simultaneously achieved in the near β-Ti alloy, based on the microscale β matrix and nanoscale α phase. The microstructure evolution, mechanical properties and strengthening mechanisms have been clarified by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the grain size of the β phase progressively decreased with the increasing of rolling reduction. Moreover, dense dislocation structures and martensite phases distributed in the cross-rolled β matrix can effectively promote the precipitation of nanoscale α particles. TEM analyses confirmed that a heat-treatment twin was generated in the newly formed α lath during aging. These findings provide insights towards developing Ti alloys with optimized mechanical properties.

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“…In this study, the results from both microhardness mapping and nanoindentation testing demonstrate strain hardening characteristics for the HPT-processed disks, which is expected from the extreme grain refinement obtained with increasing HPT revolutions. The strengthening of HPT-processed materials is commonly observed in various studies and is primarily attributed to dislocation hardening and GB strengthening, [9,63,64] as well as twinning and precipitation hardening in some metals. [1,65,66] In addition, the strain-rate dependency shown in nanoindentation testing can provide some information on the level of plasticity and plastic deformation mechanisms at different strain rates.…”

Section: Discussionmentioning

confidence: 99%

Micromechanical Response of Additively Manufactured 316L Stainless Steel Processed by High‐Pressure Torsion

et al. 2020

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Numerous studies have reported attractive properties in ultrafinegrained (UFG) and nanograined (NG) metals and alloys compared with their coarse-grained (CG) counterparts, including significantly higher yields and tensile strengths, [1-3] enhanced wear and corrosion resistance, [4-6] and superplasticity at room temperature (RT). [7,8] It is now accepted that UFG and NG materials are defined as those having grain sizes in the range of 0.1-1 μm and <100 nm, respectively. Such remarkable properties are largely attributed to grain refinement and the generation of large amounts of dislocations in these grain scales, highlighting the benefit of fine grain microstructure. [9,10] To date, severe plastic deformation (SPD) processing has emerged as one of the most popular techniques that can produce bulk metals with UFG and NG microstructures, including equal-channel angular pressing (ECAP), high-pressure torsion (HPT), and accumulative roll bonding (ARB). From these techniques, HPT has been shown as the most effective method to produce true NG structures with large amounts of highangle grain boundaries (GBs) via the application of concurrent compressive force and torsional straining on HPT-processed samples. [11] In contrast, additive manufacturing (AM) has now been utilized to fabricate metallic components for niche engineering applications, e.g., automotive, biomedical, and aerospace, due to its attractive features of design flexibility, time and cost savings, and minimal material waste. [12] Selective laser melting (SLM) is one of the most widely used AM methods in the laser powder bed fusion (LPBF) category. As its name implies, SLM uses laser as the heat source to selectively consolidate layers of the powder bed into a complete 3D structure according to the initial computer-aided design (CAD) data. To date, a wide range of alloys have been used to fabricate metallic components using SLM, including 316L stainless steel (316L SS), Inconel 718 (IN 718), AlSi 10 Mg, and Ti6Al4V. [13,14] So far, research on metal AM has focused on optimizing processing parameters to achieve the highest densification levels with minimal porosity or defect contents. [15-28] To minimize

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Exceptional grain refinement in a Mg alloy during high pressure torsion due to rare earth containing nanosized precipitates

Cited by 61 publications

References 53 publications

Processing Magnesium and Its Alloys by High‐Pressure Torsion: An Overview

Processing Magnesium and Its Alloys by High‐Pressure Torsion: An Overview

Strengthening of a Near β-Ti Alloy through β Grain Refinement and Stress-Induced α Precipitation

Micromechanical Response of Additively Manufactured 316L Stainless Steel Processed by High‐Pressure Torsion

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