Effect of Tailored Microstructures in CaO-Added AZ31 Extrusion Material on Tensile, High Cycle Fatigue and Fatigue Crack Propagation Properties

Kim, Young-Kyun; Kim, Min-Jong; Hwang, Yujin; Kim, Shae. K.; Lim, Hyun-Kyu; Lee, Kee‐Ahn

doi:10.3365/kjmm.2021.59.6.365

Cited by 3 publications

(1 citation statement)

References 24 publications

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“…Magnesium (Mg) and its alloys have received increasing attention from the aerospace, automotive, and 3C industries, largely because of their light weight, good shock absorption performance, and high specific strength [1][2][3][4]. However, the low engineering strength and strong tensile-compressive yield symmetry of extruded Mg alloys hinder their widespread application [5][6][7]. As one of solutions to these drawbacks, researchers have investigated Mg-Gd/Y-Zn [8,9] and Mg-Gd-Y-Zn alloys [10][11][12] with long-period stacking ordered (LPSO) strengthening.…”

Section: Introductionmentioning

confidence: 99%

Enhancing mechanical properties of Mg-Gd-Y-Zn alloys via microalloying with Ce and La

Zhang¹,

Kim²,

Liao³

et al. 2022

Korean J. Met. Mater.

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This study investigated the microstructure and mechanical properties of Mg-1Gd-1Y-1Zn (at.%) alloys containing designed amounts of Ce or La. The Mg5(Gd,Zn) phase formed in the as-cast Mg-Gd-Y-Zn-Ce/La alloys and disappeared after a homogenization treatment at 500°C for 24 h. The addition of Ce and La resulted in the formation of Ce(Mg,Zn)12 and La(Mg,Zn)12 phases, respectively. Except for that, the Ce or La addition had no significant effect on the morphology, volume fraction, and type of the long-period stacking ordered (LPSO) phases in the Mg-Gd-Y-Zn alloy. The grain size decreased with increasing microalloying content because the heavy Ce and La atoms impeded atomic migration across the boundaries. The solute drag effect led to the formation of the rare earth texture in the extruded Mg-Gd-Y-Zn-Ce/La alloys, whose extent decreased with increasing microalloying content. The mechanical strength was improved by the addition of Ce or La at the sacrifice of ductility. In particular, La exhibited a stronger reinforcement ability than Ce when it was added to the Mg-Gd-Y-Zn alloys. Among the investigated chemical compositions, the Mg-1Gd-1Y-1Zn-0.3La alloy exhibited the highest strength because it had the finest grains, the highest volume fraction of the second phase, and the weakest texture intensity. Furthermore, the alloys showed an unusual yield asymmetry due to the difference in the deformation mode of the LPSO phase.

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Section: Introductionmentioning

confidence: 99%

Enhancing mechanical properties of Mg-Gd-Y-Zn alloys via microalloying with Ce and La

Zhang¹,

Kim²,

Liao³

et al. 2022

Korean J. Met. Mater.

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Experimental Study on Micromechanic Behavior in Fatigue Failure of Notched Aa7075-T6 Aircraft Sheet

Leila,

FEKIRINI,

Ulyate

et al. 2024

Preprint

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Through-Thickness Microstructures and Yield Strength Enhancement for AZ31 Mg Sheets Treated by Ultrasonic Nanocrystal Surface Modification

Kang¹,

Kang²,

Park³

et al. 2022

Korean J. Met. Mater.

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An ultrasonic nanocrystal surface modification (UNSM) technique was applied to a 1-mm thick AZ31 magnesium sheet. UNSM is a relatively new surface modification technique in which a hard, hemispherical tip (2.38 mm in diameter) strikes the surface at an ultrasonic frequency to induce plastically deformed gradient microstructures and deep compressive residual stresses through the thickness. After the UNSM treatment, the through-thickness microstructures were thoroughly investigated using electron microscopy and electron backscatter diffraction analysis. The through-thickness microstructures revealed zones that were severely deformed (down to 200 µm from the surface) and twin-dominated (200~300 µm deep from the surface). The severely deformed zone consisted of shear banding, grain subdivision and reorientation, due to the strong plastic deformation, accompanied by the formation of {1012} tensile twins (despite compressive strikes by the hemispherical tip), {1011}-{1012} double twins and {1011} compression twins. The cause for tensile twinning was examined through a literature survey. In the twin-dominated zone, the twining activity prevailed as the slip activity gradually decayed through the thickness. The UNSM-induced hardness and microstructure enhancement was found to be effective down to about 300~400 μm deep from the surface. Finally, the source of the increase in yield strength after the UNSM treatment of the AZ31 sheet was analyzed, and focused on individual cases of microstructural enhancement in the severely deformed zone and the twin zone, and the compressive residual stress.

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Effect of Tailored Microstructures in CaO-Added AZ31 Extrusion Material on Tensile, High Cycle Fatigue and Fatigue Crack Propagation Properties

Cited by 3 publications

References 24 publications

Enhancing mechanical properties of Mg-Gd-Y-Zn alloys via microalloying with Ce and La

Enhancing mechanical properties of Mg-Gd-Y-Zn alloys via microalloying with Ce and La

Experimental Study on Micromechanic Behavior in Fatigue Failure of Notched Aa7075-T6 Aircraft Sheet

Through-Thickness Microstructures and Yield Strength Enhancement for AZ31 Mg Sheets Treated by Ultrasonic Nanocrystal Surface Modification

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