Age-hardening effect by phase transformation of high Sc containing Mg alloy

Ando, Daisuke; Ogawa, Yukiko; Suzuki, Teppei; Sutou, Yuji; Koike, Junichi

doi:10.1016/j.matlet.2015.06.057

Cited by 41 publications

(8 citation statements)

References 34 publications

(30 reference statements)

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“…The sample aged at 90 ks, which exhibits a saturated hardness, shows a microstructure similar to that at 18 ks. In a previous study 11) , XRD revealed that the age hardening of Mg-16.8 at%Sc alloy with a β single-phase is due to the formation of ne α precipitates. Therefore, XRD experiments were also carried out for the present aged sample.…”

Section: Aging Effect On Vickers Hardness and Microstructurementioning

confidence: 87%

“…Here, the age-hardening behavior at 473 K in the present Mg-20.5 at%Sc alloy with the β single-phase is compared to that in a reported Mg-16.8 at% Sc alloy with the β single-phase 11) . The Mg-16.8 at% alloy shows a much shorter incubation time of about 0.6 ks than the Mg-20.5 at%Sc and exhibits a maximum hardness of 220 HV for 18 ks.…”

Section: Aging Effect On Vickers Hardness and Microstructurementioning

confidence: 89%

“…The obtained samples were aged at 473 K in air and then water quenched. The aging temperature was the same as that of Mg-16.8 at% Sc which obtained a maximum average value of 220 HV 11) . The hardness of aged samples was measured by Vickers hardness tester with a load of 9.8 N, where the number of measuring points was 10 points each and the average hardness was determined by averaging 8 points except the maximum and minimum values.…”

Section: Methodsmentioning

confidence: 99%

“…Very recently, we have found that Mg-Sc alloys show high strength and elongation when their microstructure is controlled using their bcc structure 10) . Furthermore, we have reported that Mg-16.8 at% Sc alloy with a bcc single-phase shows signi cant age hardening due to the formation of a very ne hcp phase and can achieve a high hardness of over 230 HV 11) . However, the age hardened alloy was brittle and fractured in the elastic deformation region during tensile testing.…”

Section: Introductionmentioning

confidence: 99%

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Aging Effect of Mg-Sc Alloy with α+β Two-Phase Microstructure

et al. 2016

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Mg-20.5 at% Sc alloy with hcp (α)+bcc (β) two-phase was investigated to understand the effects of aging treatment at 473 K on microstructure, hardness and tensile properties. A Mg-Sc alloy ingot was prepared by induction melting in an Ar atmosphere, and then hot rolled at 873 K followed by cold rolling into a sheet. The rolled specimens were annealed at 873 K to obtain an α+β two-phase microstructure. The annealed specimens were then aged at 473 K for various time. Vickers hardness of the α+β two-phase alloy drastically increased after a certain incubation time and then reached a maximum hardness of 142.8 HV. The incubation time of the Mg-20.5 at% Sc alloy with the α+β two-phase was longer than that of the same alloy with a β single-phase. Ultimate tensile strength (UTS) and elongation of the as-annealed specimen were 280 MPa and 28.2%, respectively. Meanwhile, the specimen aged at 473 K for 14.4 ks showed a UTS of 357 MPa and an elongation of over 12%. The specimen aged for 18 ks showed a higher UTS of 465 MPa, while keeping a better elongation of 6.9%. The age hardening of the MgSc alloys was found to be due to the precipitation of very ne α phase in β phase.

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Section: Aging Effect On Vickers Hardness and Microstructurementioning

confidence: 87%

Section: Aging Effect On Vickers Hardness and Microstructurementioning

confidence: 89%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Aging Effect of Mg-Sc Alloy with α+β Two-Phase Microstructure

et al. 2016

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“…102) In addition, scandium belongs to the RE element group; hence, its atomic radius is very different from that of magnesium, and this difference highly contributes to the strengthening effect. 103) Recent numerical studies have pointed out that the electronic behavior of titanium among magnesium tends to appear as unique and interesting. This solute element plays a role in the non-basal dislocation slip activity and grain boundary strengthening (= high toughness).…”

Section: Conclusion Remarksmentioning

confidence: 99%

Effect of Alloying Elements on Fracture Toughness and Ductility in Magnesium Binary Alloys; A Review

Somekawa

2020

Mater. Trans.

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The development of magnesium alloys, which exhibit high strength and high ductility (fracture toughness), is critical for ensuring the safety and reliability in structural applications. It is well-known that grain refinement and/or alloying are impressive strategies to attain such properties in metallic materials. In the former case, grain boundaries of magnesium and its alloys have unique characteristics, e.g., sites for nonbasal dislocation activity and occurrence of partial grain boundary sliding. As a result, strength as well as ductility (fracture toughness) tend to increase and improve with grain refinement. In the latter case, 29 types of solid solution elements, which have a maximum solubility of more than 0.1 at%, can dissolve in magnesium. Several elements are generally added to magnesium simultaneously to achieve good mechanical properties via a synergistic effect. In industrial fields, ternary magnesium alloys such as MgAlZn and MgZnZr alloys, which have finegrained structures, have been widely used; however, there is no still clear and systematic understanding of the impact of various alloying elements on properties for magnesium. In this paper, we review recent studies on the effect of solid solution alloying elements on ductility (fracture toughness), with focusing on polycrystalline binary magnesium alloys. With regard to the toughness, the crack-propagation behavior and/or fracture behavior are quite sensitive to the alloying element, regardless of grain size. Twin boundaries in particular are recognized as harmful defects, because they act as crack-propagation sites. Nevertheless, changing the electric bonding behavior through alloying has the potential to increase the toughness. As for the ductility, the alloying elements also dramatically affect the room-temperature plastic deformation. In addition to the activation of the non-basal dislocation slip, grain boundary sliding also plays a notable role in enhancing the elongation-tofailure in tension.

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