Microstructural characterization, solidification characteristics and tensile properties of Al–15%Mg2Si–x(Gd–Sb) in-situ composite

Ghandvar, Hamidreza; Idris, Mohd Hasbullah; Bakar, Tuty Asma Abu; Nafari, Afshin; Ahmad, Norhayati

doi:10.1016/j.jmrt.2020.01.023

Cited by 21 publications

(8 citation statements)

References 33 publications

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“…Mg 2 Si intermetallic has many excellent properties, such as high melting temperature (1358 K), low density (1.99 Â 10 3 kg m À3 ), low thermal expansion coefficient (7.5 Â 10 À6 K À1 ), and comparatively high Young's modulus (120 GPa), which have made it as an attractive reinforcement for aluminum matrix composites. [1][2][3][4][5] Because of higher volume fraction of Mg 2 Si phase and Mg content, Al-Mg 2 Si composites have higher specific strength, excellent corrosion, and wear resistance, [6] which make Al-Mg 2 Si composites having comparatively high potential as candidates for Al-Si alloys. [7,8] It is widely used as lightweight material in aerospace, automobile, and other fields, such as safety-belt pretensioner, brake disc, and shock absorbing cover.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Microstructure and Mechanical Properties of Near‐Eutectic Al–Mg₂Si Alloys by Eu Addition

et al. 2021

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To modify the microstructure and improve the tensile properties of Al–Mg2Si alloys, different contents of Eu are added into near‐eutectic Al–Mg2Si alloys by melting. Results show that the near‐eutectic Al–Mg2Si alloys consist of primary α‐Al, the first eutectic and second eutectic (Al + Mg2Si) phases, and a few Fe‐containing phase. When the addition of Eu reaches 0.05%, the first eutectic structure is refined, and the first eutectic Mg2Si phase transforms from platelet into fiber. Meanwhile, the second eutectic phase increases, even that the alloy is almost the second eutectic phase when the Eu content is 0.3%. These changes are induced by the modification of Eu. Tensile testing shows that the ductility and the strength are improved to 8.6% and 178 MPa from 1% and 145 MPa when the Eu content is 0.05%, and fracture mode is also changed. This improvement is caused by the modification of the eutectic structure. The tensile properties are decreased or even deteriorated with further increasing the Eu content, which is induced by over‐modification of Eu addition. It is concluded that the modification of eutectic Mg2Si phase by Eu addition contributes to the enhancement of mechanical properties of the near‐eutectic Al–Mg2Si alloys.

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Section: Introductionmentioning

confidence: 99%

Improvement of Microstructure and Mechanical Properties of Near‐Eutectic Al–Mg₂Si Alloys by Eu Addition

et al. 2021

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“…However, a problem with hyper-eutectic Al–Mg 2 Si in situ composites is the coarse size of the primary Mg 2 Si phases. These coarser Mg 2 Si phases have a damaging effect on the mechanical properties of these in situ composites [ 4 , 5 , 6 ]. Therefore, many studies were conducted to enhance the mechanical properties of Al–Mg 2 Si composites by refining the primary Mg 2 Si by introducing modifier elements [ 6 , 7 , 8 , 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, many studies were conducted to enhance the mechanical properties of Al–Mg 2 Si composites by refining the primary Mg 2 Si by introducing modifier elements [ 6 , 7 , 8 , 9 , 10 ]. Ghandvar [ 4 ] studied the effect of simultaneous addition of Gd and Sb on the microstructure and corresponding mechanical properties of Al–15%Mg 2 Si composite. This resulted in a significant decrease in the size of primary Mg 2 Si phases compared to the base composition.…”

Section: Introductionmentioning

confidence: 99%

Effect of Al2Ca Addition and Heat Treatment on the Microstructure Modification and Tensile Properties of Hypo-Eutectic Al–Mg–Si Alloys

Shah

Kim

et al. 2021

Materials

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The current study investigated the microstructure modification in Al–6Mg–5Si–0.15Ti alloy (in mass %) through the minor addition of Ca using Mg + Al2Ca master alloy and heat treatment to see their impact on mechanical properties. The microstructure of unmodified alloy (without Ca) consisted of primary Al, primary Mg2Si, binary eutectic Al–Mg2Si, ternary eutectic Al–Mg2Si–Si, and iron-bearing phases. The addition of 0.05 wt% Ca resulted in significant microstructure refinement. In addition to refinement, lamellar to fibrous-type modification of binary eutectic Al–Mg2Si phases was also achieved in Ca-added (modified) alloy. This modification was related to increasing Ca-based intermetallics/compounds in the modified alloy that acted as nucleation sites for binary eutectic Al–Mg2Si phases. The dendritic refinement with Ca addition was related to the fact that it improves the efficacy of Ti-based particles (TiAl3 and TiB2) in the melt to act as nucleation sites. In contrast, the occupation of oxide bifilms by Ca-based phases is expected to force the iron-bearing phases (as iron-bearing phases nucleate at oxide films) to solidify at lower temperatures, thus reducing their size. The as-cast microstructure of these alloys was further modified by subjecting them to solution treatment at 540 °C for 6 h, which broke the eutectic structure and redistributed Mg2Si and Si phases in Al-matrix. Subsequent aging treatment caused a dramatic increase in the tensile strength of these alloys, and tensile strength of 291 MPa (with El% of 0.45%) and 327 MPa (with El% of 0.76%) was achieved for the unmodified alloy and modified alloy, respectively. Higher tensile strength and elongation of the modified alloy than unmodified alloy was attributed to refined dendritic structure and modified second phases.

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“…According to this diagram, eutectic transformation proceeds at 1.48 wt% silicon, and materials from the Mg–Si system are divided into hypoeutectic, eutectic and hypereutectic. These composites can be fabricated by both powder metallurgy [ 22 , 23 , 24 , 25 , 26 , 27 , 28 ] and the casting process [ 6 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. Compared to other methods, casting is a method that can be easily adapted to the required commercial scale of production and is the most economical.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, Mg/Mg 2 Si composites have been intensively investigated due to the number of properties of the Mg 2 Si phase such as low density (1.99 g/cm 3 ), a comparatively low thermal expansion coefficient (7.5 × 10 −6 K −1 ), relatively high Young’s modulus (120 GPa) and high hardness (4.5 × 10 9 Pa) [ 17 , 18 , 19 , 20 , 21 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. It should be additionally noted that the Mg 2 Si compound is also used as a reinforcing phase of aluminum matrix composites [ 37 , 38 , 39 , 40 , 41 , 42 , 43 ] or as a component of magnesium matrix composites with SiC or aluminosilicate microspheres [ 27 , 44 , 45 ]. However, Mg/Mg 2 Si materials were most often investigated in separate experiments where composites with different weight fractions of silicon (i.e., the Mg 2 Si phase) were analyzed.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of Hypo- and Hypereutectic Cast Mg/Mg2Si Composites

Braszczyńska-Malik

Malik

2020

Materials

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In this paper, the microstructure and mechanical properties of two magnesium matrix composites—a hypoeutectic with 1.9 wt% Mg2Si phase and a hypereutectic with 19 wt% Mg2Si compound—were analyzed. The investigated materials were prepared using the gravity casting method. Microstructure analyses of the fabricated composites were carried out by XRD and light microscopy. The tensile and compression strength as well as yield strength of the composites were examined in both uniaxial tensile and compression tests. The microstructure of the hypoeutectic composite was in agreement with the phase diagram and composed of primary Mg dendrites and an Mg–Mg2Si eutectic mixture. For the hypereutectic composite, besides the primary Mg2Si phase and eutectic mixture, additional magnesium dendrites surrounding the Mg2Si compound were observed due to nonequilibrium solidification conditions. The composites exhibited a rise in the examined mechanical properties with an increase in the Mg2Si weight fraction and also a higher tensile and compression strength in comparison to the pure magnesium matrix (cast in the same conditions). Additionally, analyses of fracture surfaces of the composites carried out using scanning electron microscopy (SEM + EDX) are presented.

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Microstructural characterization, solidification characteristics and tensile properties of Al–15%Mg2Si–x(Gd–Sb) in-situ composite

Cited by 21 publications

References 33 publications

Improvement of Microstructure and Mechanical Properties of Near‐Eutectic Al–Mg₂Si Alloys by Eu Addition

Improvement of Microstructure and Mechanical Properties of Near‐Eutectic Al–Mg₂Si Alloys by Eu Addition

Effect of Al2Ca Addition and Heat Treatment on the Microstructure Modification and Tensile Properties of Hypo-Eutectic Al–Mg–Si Alloys

Microstructure and Mechanical Properties of Hypo- and Hypereutectic Cast Mg/Mg2Si Composites

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Microstructural characterization, solidification characteristics and tensile properties of Al–15%Mg2Si–x(Gd–Sb) in-situ composite

Cited by 21 publications

References 33 publications

Improvement of Microstructure and Mechanical Properties of Near‐Eutectic Al–Mg2Si Alloys by Eu Addition

Improvement of Microstructure and Mechanical Properties of Near‐Eutectic Al–Mg2Si Alloys by Eu Addition

Effect of Al2Ca Addition and Heat Treatment on the Microstructure Modification and Tensile Properties of Hypo-Eutectic Al–Mg–Si Alloys

Microstructure and Mechanical Properties of Hypo- and Hypereutectic Cast Mg/Mg2Si Composites

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Improvement of Microstructure and Mechanical Properties of Near‐Eutectic Al–Mg₂Si Alloys by Eu Addition

Improvement of Microstructure and Mechanical Properties of Near‐Eutectic Al–Mg₂Si Alloys by Eu Addition