Cast magnesium alloys for elevated temperature applications

Luo, Alan A.; Pekguleryuz, Mihriban

doi:10.1007/bf01171534

Cited by 538 publications

(230 citation statements)

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“…Conversely, although Al 11 RE 3 has a body-centered orthorhombic structure, 24,25) which is incoherent with the hcp lattice of the magnesium matrix, its high melting point (>1513 K), 26) strong intermetallic bonding, and the low diffusion rate of RE elements in magnesium all result in a thermally stable alloy, even at 773 K. 12,27) Thus, during deformation at 300 K (room temperature), both precipitates and Al 11 RE 3 dispersions obstruct the motion of dislocations, strengthening these alloys. The effect remains up to 473 K for cast and hot extruded Mg-8Al-xRE alloys.…”

Section: )mentioning

confidence: 99%

Tensile Properties of Mg-8Al-xRE Alloys from 300 K to 673 K

Yang

Koo

2003

Mater. Trans.

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This paper presents the tensile properties of cast and extruded Mg-8Al-xRE (in mass%; x is 0, 1, 2 or 3%) alloys from 300 to 673 K obtained at a strain rate of 8:3 Â 10 À4 s À1 . Mg-8Al-xRE alloys were prepared by melting and casting in a vacuum induction furnace, and extruded at 633 K with a reduction ratio of 90 : 1. RE greatly improves the tensile strength of cast and extruded Mg8Al alloys above 473 K. RE negatively affects the elongation of cast alloys at the studied temperature range but considerably enhances that of extruded alloys. Superplasticity of the extruded alloys is observed at 473 K or above. The strengthening mechanisms and the optimal deformation temperature, T c , of these alloys are discussed in detail.

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Section: )mentioning

confidence: 99%

Tensile Properties of Mg-8Al-xRE Alloys from 300 K to 673 K

Yang

Koo

2003

Mater. Trans.

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Section: Creep Deformationmentioning

confidence: 99%

“…WE54 is the most commercially used structural Mg alloys for elevated-temperature applications up to 523K, [2,17,18] and HZ32 is the Mg alloy which has been used at the highest service temperatures (618≤T≤643K). [2,6] However, HZ32 is being phased out due to its radioactivity. [6,18] The peak-aged WGZ1152-T6 exhibited superior creep resistance compared to the WE54-T6 at T=523-573K (0.58-0.64T m ) and σ=50-80MPa, and was comparable to the HZ32-T5 at T=573K and σ=30MPa.…”

Section: Creep Deformationmentioning

confidence: 99%

“…[1][2][3][4] In addition to the aerospace industry, Mg alloys have made significant progress in the automotive industry where weight and fuel economy are important considerations. [1,3] Most commercially used Mg alloys for automotive applications are Mg-Al based alloys, such as AZ (Mg-Al-Zn) series and AM (Mg-Al-Mn) series, and they can't be used for major powertrain applications due to their poor creep resistance at temperatures above 398K.…”

Section: Introductionmentioning

confidence: 99%

“…[6] The addition of rare earth (RE) elements to Mg alloy can lead to increased creep resistance at temperatures up to 573K. [1][2][3]6,7] Rare earths can be divided into two groups: Y group (Y, Gd-Lu) and Ce group (La-Eu). [1,6,7] The Y group has higher solid solution strengthening and precipitation hardening.…”

Section: Introductionmentioning

confidence: 99%

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Creep and Fracture Behavior of Peak-Aged Mg-11Y-5Gd-2Zn-0.5Zr (wt pct)

Yin

Wang

Boehlert

et al. 2012

Metall Mater Trans A

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The tensile-creep and creep-rupture behavior of heat-resistant peak-aged Mg-11Y-5Gd-2Zn-0.5Zr (wt.%) (WGZ1152) was investigated at T=523-598K (0.58-0.66T m ) and stresses between 30MPa to 140MPa. The minimum creep rate of the alloy was almost two orders of magnitude lower than that for WE54-T6, and was comparable to that for HZ32-T5. The creep behavior exhibited an extended tertiary creep stage, which was believed to be associated with precipitate coarsening. The creep stress exponent value was 4.5, suggesting that dislocation creep was the rate-controlling mechanism. The activation energy for creep (221±20kJ/mol) was higher than that for self-diffusion in magnesium, and was believed to be associated with the activation of non-basal slip and cross slip. This was consistent with the surface deformation observations, which revealed a transition from basal slip to non-basal slip and cross slip with increasing temperature. The minimum creep rate and rupture time followed the original and modified Monkman-Grant relationships. The microcracks and cavities preferentially nucleated at grain boundaries and at the interface between Mg matrix and the second phase. In-situ creep experiments highlighted the intergranular cracking evolution.

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