Ultrasound-assisted casting of AZ91D-1.5%Ca – Shifting T4 paradigm for downstream processing

Gomes, I. V.; D’Errico, Fabrizio; Alves, J. L.; Puga, Hélder

doi:10.1016/j.matlet.2022.133305

Cited by 3 publications

(4 citation statements)

References 11 publications

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“…The discrepancies observed in the materials' response to the solution treatment may have been promoted by their different as-cast microstructures. Regardless of the processing procedure, the microstructure of the as-cast samples is composed of α-Mg, β-Mg 17 Al 12 , Al 2 Ca, and Al-Mn rich phases, as observed in our previous work [23]. However, significantly different morphologic characteristics could be observed, which may be attributable to the application of ultrasonic vibrations to the solidifying melt.…”

Section: Methodssupporting

confidence: 60%

“…These alloys have demonstrated excellent results of ignition resistance allied to excellent strength-to-weight ratio, granting an increasing interest in them recently [21,22]. However, adding calcium is known to lead to the formation of thermally stable Al-Ca intermetallics, changing the fraction of the β-Mg 17 Al 12 phase formed during solidification and heat treatment [23].…”

Section: Introductionmentioning

confidence: 99%

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On the Aging Kinetics of a Flame-Resistant AZ91D-1.5%Ca Magnesium Alloy Processed with Ultrasonic Vibration

et al. 2023

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The Mg-Al-Zn-Ca system has demonstrated excellent flame resistance and mechanical properties in the as-cast condition. However, the potential of these alloys to be heat-treated, e.g., by aging, as well as the influence of the initial microstructure on the precipitation kinetics, is yet to be comprehensively explored. Ultrasound treatment was applied during the solidification of an AZ91D-1.5%Ca alloy to promote microstructure refinement. Samples from treated and non-treated ingots were subjected to solution treatment at 415 °C for 480 min, followed by aging at 175 °C for up to 4920 min. The results showed that the ultrasound-treated material could reach the peak-age condition in a shorter period than the non-treated one, suggesting accelerated precipitation kinetics and, thus, enhanced aging response. However, the tensile properties showed a decrease in the peak age compared to the as-cast condition, probably due to the formation of precipitates at the grain boundaries that promote the formation of microcracks and intergranular early fracture. This research shows that tailoring the material’s as-cast microstructure may positively affect its aging response, shortening the heat treatment duration, thereby making the process less expensive and more sustainable.

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Section: Methodssupporting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

On the Aging Kinetics of a Flame-Resistant AZ91D-1.5%Ca Magnesium Alloy Processed with Ultrasonic Vibration

et al. 2023

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“…Only α-Mg can be detected in the dark black matrix, and the Mg 17 Al 12 phase was precipitated in gray–white granular and chain structures. The needle-like phase and white circular particles were thought to be Al 2 Ca [ 40 ] and Al 4 Mn, respectively. The XRD results in Figure 7 further confirm the above speculation.…”

Section: Resultsmentioning

confidence: 99%

“…It is well known that the Ca add to AZ91 alloy will exist in the form of solid solution and high-melting-point Al 2 Ca phase with different additions [ 27 , 31 , 40 ]. When the content of Ca does not exceed 0.1 wt.%, it is well dissolved into α-Mg matrix and Mg 17 Al 12 phase.…”

Section: Discussionmentioning

confidence: 99%

Improvement of Hot Tearing Resistance of AZ91 Alloy with the Addition of Trace Ca

et al. 2023

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Hot tearing is the most common and serious casting defect that restricts the light weight and integration of magnesium alloy components. In the present study, trace Ca (0–1.0 wt.%) was added to improve the resistance of AZ91 alloy to hot tearing. The hot tearing susceptivity (HTS) of alloys was experimentally measured by a constraint rod casting method. The results indicate that the HTS presents a ν-shaped tendency with the increase in Ca content, and reaches its minimum value in AZ91–0.1Ca alloy. Ca is well dissolved into α-Mg matrix and Mg17Al12 phase at an addition not exceeding 0.1 wt.%. The solid-solution behavior of Ca increases eutectic content and its corresponding liquid film thickness, improves the strength of dendrites at high temperature, and thereby promotes the hot tearing resistance of the alloy. Al2Ca phases appear and aggregate at dendrite boundaries with further increases in Ca above 0.1 wt.%. The coarsened Al2Ca phase hinders the feeding channel and causes stress concentration during the solidification shrinkage, thereby deteriorating the hot tearing resistance of the alloy. These findings were further verified by fracture morphology observations and microscopic strain analysis near the fracture surface based on kernel average misorientation (KAM).

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Shielding AZ91D-1%Ca from corrosion through ultrasound melt treatment: A study for stent design

Gomes,

Pacheco,

Nienaber

et al. 2023

Journal of Magnesium and Alloys

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Ultrasound-assisted casting of AZ91D-1.5%Ca – Shifting T4 paradigm for downstream processing

Cited by 3 publications

References 11 publications

On the Aging Kinetics of a Flame-Resistant AZ91D-1.5%Ca Magnesium Alloy Processed with Ultrasonic Vibration

On the Aging Kinetics of a Flame-Resistant AZ91D-1.5%Ca Magnesium Alloy Processed with Ultrasonic Vibration

Improvement of Hot Tearing Resistance of AZ91 Alloy with the Addition of Trace Ca

Shielding AZ91D-1%Ca from corrosion through ultrasound melt treatment: A study for stent design

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