Unexpected influence of Mn addition on the creep properties of a cast Mg–2Al–2Ca (mass%) alloy

Homma, Tomoyuki; Nakawaki, S.; Oh-ishi, Keiichiro; Hono, K.; Kamado, Shigeharu

doi:10.1016/j.actamat.2011.08.049

Cited by 84 publications

(19 citation statements)

References 24 publications

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“…Certain alloying additions such as; Ca, Y and rare-earths also cause solid solution strengthening that slows down dislocation motion due to strain energy of atomic misfit, dislocation drag force and/or the decrease in stacking fault energy (SFE) of Mg [23]. The addition of Mn, on the other hand, does not cause much solid solution strengthening in Mg; this has been attributed to the fact that Mn increases the SFE of Mg which also increases the minimum strain rate of dislocation climb [13,24].…”

Section: Theoretical Backgroundmentioning

confidence: 96%

“…Effective solid-solution strengthening is known to increase the duration of primary creep stage in Mg-Al-Ca alloys (MRI153) [30]. The solute strengthening due to Mg(Mn) is known to be negligible due to an increase in the stacking fault energy (SFE) [24]. Hence, as creep deformation commences in the primary creep stage, dislocations glide easily due to low solute strengthening and the pile-up of dislocations occurs at the dendritic-phase boundaries.…”

Section: Primary Creepmentioning

confidence: 99%

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The role of α-Mn precipitation on the creep mechanisms of Mg–Sr–Mn

Çelikin¹,

Pekguleryuz²

2012

Materials Science and Engineering: A

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Section: Theoretical Backgroundmentioning

confidence: 96%

Section: Primary Creepmentioning

confidence: 99%

The role of α-Mn precipitation on the creep mechanisms of Mg–Sr–Mn

Çelikin¹,

Pekguleryuz²

2012

Materials Science and Engineering: A

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“…In a subsequent study, [44] it was reported that the same alloy exhibits an age-hardening phenomenon when it is aged at 448 K to 523 K (175°C to 250°C) and that this age-hardening response is caused by the precipitation of the C15 plates. In a very recent study [45] of Mg-2Al-2Ca and Mg-2Al-2Ca-0.3Mn (wt pct) alloys, which were produced by permanent mold casting and creep tested at 448 K and 473 K (175°C and 200°C) under 50 MPa, the C15 plates were observed to form in the as-cast microstructures of the two alloys, and ordered G.P. zones form on the basal plane of the matrix phase in the crept samples.…”

Section: C15mentioning

confidence: 99%

Precipitation and Hardening in Magnesium Alloys

Nie

2012

Metall Mater Trans A

1,397

519

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Magnesium alloys have received an increasing interest in the past 12 years for potential applications in the automotive, aircraft, aerospace, and electronic industries. Many of these alloys are strong because of solid-state precipitates that are produced by an age-hardening process. Although some strength improvements of existing magnesium alloys have been made and some novel alloys with improved strength have been developed, the strength level that has been achieved so far is still substantially lower than that obtained in counterpart aluminum alloys. Further improvements in the alloy strength require a better understanding of the structure, morphology, orientation of precipitates, effects of precipitate morphology, and orientation on the strengthening and microstructural factors that are important in controlling the nucleation and growth of these precipitates. In this review, precipitation in most precipitation-hardenable magnesium alloys is reviewed, and its relationship with strengthening is examined. It is demonstrated that the precipitation phenomena in these alloys, especially in the very early stage of the precipitation process, are still far from being well understood, and many fundamental issues remain unsolved even after some extensive and concerted efforts made in the past 12 years. The challenges associated with precipitation hardening and age hardening are identified and discussed, and guidelines are outlined for the rational design and development of higher strength, and ultimately ultrahigh strength, magnesium alloys via precipitation hardening.

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“…The improvement in creep resistance by minor Mn additions has been reported in several Mg-Al based alloys, including Mg-6Al-2Sr-0.3Mn, [22] Mg-6Al-3Ca-0.5Mn, [23] and Mg-2Al-2Ca-0.3Mn. [24] The positive effect of Mn on creep resistance in these alloys was attributed to the presence and/or dynamic precipitation of Al-Mn nanoscale precipitates [22,23] or Al-Mn GP zones. [24] We expect that Mn content is another factor that contributes to the observed large differences in creep resistance of the current AE44 alloys.…”

Section: Resultsmentioning

confidence: 99%

“…[24] The positive effect of Mn on creep resistance in these alloys was attributed to the presence and/or dynamic precipitation of Al-Mn nanoscale precipitates [22,23] or Al-Mn GP zones. [24] We expect that Mn content is another factor that contributes to the observed large differences in creep resistance of the current AE44 alloys. Work is ongoing to further investigate the influence of Mn additions on creep resistance of Mg-Al-RE alloys, which will be reported on later.…”

Section: Resultsmentioning

confidence: 99%

The Influence of Individual Rare Earth Elements (La, Ce, or Nd) on Creep Resistance of Die‐Cast Magnesium Alloy AE44

Zhu

Easton

Abbott³

et al. 2016

Adv Eng Mater

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Three AE44 (Mg-4Al-4RE, wt%) alloys are prepared from individual RE elements, i.e., La, Ce, or Nd, by high-pressure die casting and the creep resistance of these alloys is evaluated. It is shown that the choice of RE elements has a significant influence on the creep resistance of AE44, with the La-containing alloy being the most creep-resistant while the Nd-containing alloy the least creepresistant. Microstructural examinations suggest that the observed difference in creep resistance cannot be accounted for by the thermal stability of the Al 11 RE 3 phase, as reported previously, but can be related to the volume fraction of intermetallic phases and the content of manganese.Mg-Al-rare earth (RE) alloys are one of the families of magnesium die casting alloys developed for elevated temperature applications such as automotive powertrains where the operating temperatures can be as high as 200 C. The two important alloys in the Mg-Al-RE family are AE42 (Mg-4Al-2RE, compositions in wt% throughout unless specified) and AE44 (Mg-4Al-4RE

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Unexpected influence of Mn addition on the creep properties of a cast Mg–2Al–2Ca (mass%) alloy

Cited by 84 publications

References 24 publications

The role of α-Mn precipitation on the creep mechanisms of Mg–Sr–Mn

The role of α-Mn precipitation on the creep mechanisms of Mg–Sr–Mn

Precipitation and Hardening in Magnesium Alloys

The Influence of Individual Rare Earth Elements (La, Ce, or Nd) on Creep Resistance of Die‐Cast Magnesium Alloy AE44

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