On the role of Laves phases on the mechanical properties of Mg-Al-Ca alloys

Zubair, Muhammad; Sandlöbes, Stefanie; Wollenweber, Maximilian A.; Kusche, Carl F.; Hildebrandt, Wilhelm; Broeckmann, C.; Korte‐Kerzel, Sandra

doi:10.1016/j.msea.2019.04.048

Cited by 66 publications

(47 citation statements)

References 51 publications

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“…Similar microstructures were also observed before in other Mg-Al-Ca alloys [16,20,40]. The average dendrite cell is slightly lower and the area fraction of Laves phase slightly higher than the values reported for a similar Mg-Al-Ca alloy (with a Ca/Al ratio of 0.6) in our previous work [16]. On the other hand, the σ0.2 and UTS of the present alloy at both temperatures (RT and 170 °C) are significantly higher.…”

Section: Microstructure and Mechanical Propertiessupporting

confidence: 90%

“…For the evaluation of the change in local connectivity of the 2D Laves phase network as a function of composition and deformation, SEM images of the same sample positions before and after tensile deformation were used. Images taken on the sample prepared in this work were further compared with samples possessing different Ca/Al ratios produced in the same way and discussed in terms of their mechanical properties in our previous work [16]. Images were smoothed with a bilateral filter and the 2D networks were segmented using global gray value thresholds.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…The two other Laves phases of the Mg-Al-Ca system, namely, (Mg,Al)2Ca and Mg2Ca, were also reported to form in Mg-Al-Ca alloys [12][13][14][15]. It was reported that the Ca/Al ratio controls which Laves phases form: the type of Laves phase changes from Al2Ca (C15) to (Mg,Al)2Ca (C36) and Mg2Ca (C14) with variation of the Ca/Al ratio from 0.3 to 1.0 [12,16]. 3 The alloy Mg-5Al-3Ca (in wt.%) (from here onwards referred to as AX53) has a dual phase microstructure, containing a hard intermetallic skeleton of (Mg,Al)2Ca Laves phase embedded in a soft α-Mg matrix [16].…”

Section: Introductionmentioning

confidence: 99%

“…It was reported that the Ca/Al ratio controls which Laves phases form: the type of Laves phase changes from Al2Ca (C15) to (Mg,Al)2Ca (C36) and Mg2Ca (C14) with variation of the Ca/Al ratio from 0.3 to 1.0 [12,16]. 3 The alloy Mg-5Al-3Ca (in wt.%) (from here onwards referred to as AX53) has a dual phase microstructure, containing a hard intermetallic skeleton of (Mg,Al)2Ca Laves phase embedded in a soft α-Mg matrix [16]. Due to significantly different intrinsic mechanical properties of the different phases (α-Mg matrix and Laves phases) [17][18][19], a highly heterogeneous strain distribution was reported for Mg-Al-Ca alloys [16,20].…”

Section: Introductionmentioning

confidence: 99%

“…3 The alloy Mg-5Al-3Ca (in wt.%) (from here onwards referred to as AX53) has a dual phase microstructure, containing a hard intermetallic skeleton of (Mg,Al)2Ca Laves phase embedded in a soft α-Mg matrix [16]. Due to significantly different intrinsic mechanical properties of the different phases (α-Mg matrix and Laves phases) [17][18][19], a highly heterogeneous strain distribution was reported for Mg-Al-Ca alloys [16,20]. In addition, the volume fraction, morphology, distribution, and orientation relationship between matrix and second phase can affect the strain heterogeneity.…”

Section: Introductionmentioning

confidence: 99%

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Strain heterogeneity and micro-damage nucleation under tensile stresses in an Mg–5Al–3Ca alloy with an intermetallic skeleton

Zubair

Sandlöbes-Haut

Wollenweber

et al. 2019

Materials Science and Engineering: A

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Strain heterogeneity at the microstructural level plays a vital role in the deformation and fracture behaviour of dual or multi-phase materials. In the present work, the strain heterogeneity, localization and partitioning arising at the sub-micron scale during elevated temperature (170 °C) tensile deformation of an Mg-5Al-3Ca alloy was investigated using quasi in-situ μ-DIC experiments. The results reveal that the strain is mainly carried by the α-Mg phase, while the intermetallic Laves phase plays a critical role in that strain concentrations build up at the α-Mg matrix and Laves phase interfaces, hence, reducing the overall deformability of the alloy. In quasi in-situ and bulk material analysis at elevated temperature, cracks were observed to nucleate in the Laves phase, at i) the intersection points of slip lines in the α-Mg matrix with the Laves phase and ii) the twin intersections with α-Mg/Laves phase interfaces and iii) twin transmissions across α-Mg/Laves phase interfaces. Euler number analysis has shown that the (inter-)connectivity of the Laves phase decreases with deformation. Finally, cracks grow preferentially along the Laves phases until the material fractures.

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Section: Microstructure and Mechanical Propertiessupporting

confidence: 90%

Section: Experimental Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Strain heterogeneity and micro-damage nucleation under tensile stresses in an Mg–5Al–3Ca alloy with an intermetallic skeleton

Zubair

Sandlöbes-Haut

Wollenweber

et al. 2019

Materials Science and Engineering: A

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Determination of the Rate Dependence of Damage Formation in Metallic‐Intermetallic Mg–Al–Ca Composites at Elevated Temperature using Panoramic Image Analysis

Medghalchi,

Zubair,

Karimi

et al. 2023

Adv Eng Mater

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We study a cast Mg‐4.65Al‐2.82Ca alloy with a microstructure containing an α‐Mg matrix, reinforced with a C36 Laves phase skeleton. Such ternary alloys are targeted for elevated temperature applications in automotive engines, since they possess excellent creep properties. However, in application, the alloy may be subjected to a wide range of strain rates, and thus accelerated testing is often essential. It is, therefore, crucial to understand the effect of such rate variations. Here, we focus on their impact on damage formation. Our analysis is based on high resolution panoramic imaging using scanning electron microscopy, combined with automated damage analysis using deep learning for object detection and classification (YOLOv5). We find, that with decreasing strain rate the dominant damage mechanism for a given strain level changes: at a strain rate of 5•10‐4/s, the evolution of microcracks in the C36 Laves phase dominates damage formation. However, when the strain rate is decreased to 5•10‐6/s, interface decohesion at the α‐Mg/Laves phase interfaces becomes equally important. We also observe a change in crack orientation, indicating an increasing influence of plastic co‐deformation of the α‐Mg matrix and Laves phase. We attribute this transition in the leading damage mechanism to thermally activated processes at the interface.This article is protected by copyright. All rights reserved.

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Influence of Al and Ca on the Ductility of Mg–Al–Ca Alloys

Delis,

Huckfeldt,

Hallstedt

et al. 2023

Adv Eng Mater

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Mg and its alloys offer huge potential for lightweight applications. However, many Mg alloys suffer from limited room temperature formability. It has previously been shown that the addition of Al and Ca to Mg can improve ductility. Therefore, the aim of the present work is to systematically vary the alloying content of Al and Ca and to study their effects on the slip system activity and crystallographic texture after rolling and recrystallisation. Our results show that all investigated ternary alloys in the range of 1‐2 wt.‐% Al and 0.005‐0.5 wt.‐% Ca have an increased ductility (in the range of 10‐17 % increase compared to pure Mg), whereas the binary Mg‐Al and Mg‐Ca alloys suffer from limited ductility (10% tensile elongation) and strength (175 MPa ultimate tensile strength). Non‐basal and especially <c+a>‐slip was active in all compositions (in 15‐33% of the grains examined). Basal‐type textures were observed for all compositions, but with significantly weaker basal peak intensities for Ca‐containing samples when compared to pure Mg. The combination of activation of the <c+a> slip system and texture weakening is discussed as being responsible for the improved ductility of the ternary Mg‐Al‐Ca alloys.This article is protected by copyright. All rights reserved.

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On the role of Laves phases on the mechanical properties of Mg-Al-Ca alloys

Cited by 66 publications

References 51 publications

Strain heterogeneity and micro-damage nucleation under tensile stresses in an Mg–5Al–3Ca alloy with an intermetallic skeleton

Strain heterogeneity and micro-damage nucleation under tensile stresses in an Mg–5Al–3Ca alloy with an intermetallic skeleton

Determination of the Rate Dependence of Damage Formation in Metallic‐Intermetallic Mg–Al–Ca Composites at Elevated Temperature using Panoramic Image Analysis

Influence of Al and Ca on the Ductility of Mg–Al–Ca Alloys

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