The Analysis of Strontium Modification on Microstructure and Mechanical Properties of Al-25%Mg2Si In Situ Composite

Wang, Dongtao; Zhang, Haitao; Han, Xing; Shao, Bo; Li, Lei; Chen, Jianzhong

doi:10.1007/s11665-017-2889-y

Cited by 16 publications

(6 citation statements)

References 14 publications

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“…Al-Mg 2 Si composite is typically in-situ produced by adding Mg and Si to aluminum melt in excess of their solubility limits. [1][2][3][4][5][6] In the hypereutectic condition, the Mg 2 Si phase (akin to a ceramic reinforcement) precipitates into the aluminum matrix in two forms which are primary particles and secondary flake-like networks, respectively. These precipitates create suitable properties such as high melting temperature (1085 C), low density (1.99 Â 10 3 kg m À3 ), high hardness (4500 MN m À2 ), low thermal expansion coefficient (7.5 Â 10 À6 K À1 ), and high elastic modulus.…”

Section: Introductionmentioning

confidence: 99%

“…These precipitates create suitable properties such as high melting temperature (1085 C), low density (1.99 Â 10 3 kg m À3 ), high hardness (4500 MN m À2 ), low thermal expansion coefficient (7.5 Â 10 À6 K À1 ), and high elastic modulus. [1][2][3]7 Based on this attribute, Al-Mg 2 Si MMC is suggested as a practical substitute for steel and cast iron used in automobile, airplane, and machine-manufacturing industries for the production of different components like brake disc and wear-resistant pieces. 3,[7][8][9] Unfortunately, in the Al-Mg 2 Si samples produced via conventional casting methods, the morphology of the primary reinforcement particles is dendritic or irregular in nature, consequently, they are non-homogeneously distributed in the Al matrix.…”

Section: Introductionmentioning

confidence: 99%

“…2,3,8 A lot of studies have been carried out in order to improve the structure and mechanical properties of this composite. For instance, several reports have been presented about the effect of adding different alloying elements as a modifier during melting [1][2][3]10,11 and about thermo-mechanical working methods as a secondary process after solidification. [12][13][14][15][16] These methods have assisted in the modification of both primary and secondary reinforcement phases (more homogenous distribution), bond strength improvement, and reduction of porosities in Al-Mg 2 Si composites.…”

Section: Introductionmentioning

confidence: 99%

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Role of Mg₂Si particles on mechanical, wear, and corrosion behaviors of friction stir welding of AA6061-T6 and Al-Mg₂Si composite

Moharami

Razaghian

Babaei

et al. 2020

Journal of Composite Materials

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This paper investigates the effect of different tool pin morphologies on the inter-mixing capability, microstructure, mechanical properties, corrosion, fracture, and wear behaviors of the dissimilar friction stir welded AA6061-T6 alloy--Al 20wt% Mg2Si composite. Grooved shoulder tools with varying pin profiles such as tapered cylindrical, threaded tapered cylindrical, and triangular tapered pins were used for joining the base materials. The parameter combination of 80 mm/min travel speed and 1000 r/min rotation speed (at which no visible flow-induced defect was obtained) was used for this study. Among the pin profiles, the triangular tapered pin produced significantly improved intermingling/inter-material flow, fragmentation, and dispersion of the primary Mg2Si particles in the AA6061-T6/Al-Mg2Si joint. The triangular tapered tool reduced the average grain sizes of the AA6061 alloy and the Mg2Si particles from 18.4 to 4.6 µm and from 115 to 7.5 µm, respectively. Intermetallic phases of Mg2Si, AlFe, Al3.21Si0.47, and Al0.7Fe3Si0.3 are formed in the weld nugget of all the AA6061/Al-Mg2Si joints. The tensile strengths of the joints fabricated with tapered cylindrical, threaded tapered cylindrical, and triangular tapered tools are 108, 139, and 141 MPa, respectively. Abrasive wear is promoted in the joints fabricated with triangular tapered tool due to the homogeneous dispersion and fragmentation of the inherent hard Mg2Si particles. The corrosion attack is dependent on the fragmentation level of the Mg2Si phase. Triangular tapered pin tool is recommended for dissimilar Al/composite welding due to favorable tool-induced material flow, dispersion, and fragmentation of reinforcement.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Role of Mg₂Si particles on mechanical, wear, and corrosion behaviors of friction stir welding of AA6061-T6 and Al-Mg₂Si composite

Moharami

Razaghian

Babaei

et al. 2020

Journal of Composite Materials

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“…Interestingly, the truncated octahedron is obtained by combined addition of Sr and Bi, thus, the result shows the

\sqrt{3} / 3

< R * <

\sqrt{3}

. Recently, it was widely accepted that modification mechanism of Sr was considered as absorption effect . As for modification mechanism of Bi, it may be related to that Bi restricts the growth of Mg 2 Si crystal by poisoning some growing sites on the surface of the Mg 2 Si nuclei and composition supercooling caused by the segregation of Bi at the front of liquid/solid interface of Mg 2 Si .…”

Section: Discussionmentioning

confidence: 98%

High Performance of T6‐Treated Al–15Mg₂Si–3Cu Composite Reinforced with Spherical Primary Mg₂Si after the Co‐Modification of Bi + Sr

Chong

Zhao

et al. 2019

Adv Eng Mater

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In this work, the effect of the addition of Bi combined with T6 treatment on microstructure and tensile properties of Sr-modified Al-15Mg 2 Si-3Cu composite is investigated. The results show that the refinement effect of Sr on primary Mg 2 Si is further enhanced via the combined addition of Bi. Interestingly, the truncated octahedral primary Mg 2 Si with the smallest size (11.5 μm) is obtained by adding 0.1% Sr and 1% Bi, which is distinctly different from the cubic shape modified by single 0.1% Sr. Consequently, as a precursor with strong diffusion of Mg and Si atoms during T6 treatment, the truncated octahedral primary Mg 2 Si is completely transformed into spherical morphology with the highest sphericity (0.92) solution treated at 500 C for 6 h. Additionally, further results reveal that the co-modification of Sr þ Bi is more efficient not only in promoting the spheroidization of primary Mg 2 Si, but also obtaining the fine dot-like eutectic Mg 2 Si than single modification of Sr or Bi. As a result, the tensile strength and elongation are significantly enhanced to 374 MPa and 4.75%, respectively. Thereby, this work offers an alternative co-modification system combined with T6 treatment to synthesize the spherical primary Mg 2 Si, which is helpful to prepare the high performance Al-Mg 2 Si composite.

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“…Characterization of the effect of melt treatments on melt quality in Al-7wt %Si-Mg alloys was investigated by Uludag et al [40] who found that, in both degassed and non-degassed melts, Sr additions degraded the melt quality significantly. Another source to be considered is oxide films, mainly Al 2 O 3 and SrO [40][41][42][43][44]. Dispinar and Campbell [45] proposed the concept of bifilms defined as folding/unfolding and furling/unfurling mechanism.…”

Section: 3mentioning

confidence: 99%

A Review Study on the Main Sources of Porosity in Al‐Si Cast Alloys

Samuel

Zedan

Doty

et al. 2021

Advances in Materials Science and Engineering

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The present study was performed on A356 and B319 alloys in mechanically stirred or degassed condition. Melts were Sr-modified and grain-refined. Hydrogen content was varied from less than 0.1 ml/100 g Al to ∼0.4 ml/100 g Al; Fe was increased to 0.8% in B319 alloy. Lanthanum and cerium were added as 99.5% pure metals. Two main techniques were used to investigate porosity formation: fracture surface of tensile or fatigue test bars, or reduced pressure test (RPT) method. Porosity type and shape were examined. The results show that pore size is more influential than small scattered ones from a mechanical point of view. Tensile testing is affected by porosity located at the center of the testing bar, whereas edge porosity is responsible for crack initiation in case of fatigue testing. Intermetallics precipitate in the form of intercepted platelets which restricts the flow of the molten metal, leading to formation of shrinkage cavities. Precipitation of clusters of compounds from the liquid state such as Al2Si2Sr, Mg2Sn, Al3Ti, or added Al2O3particles would as well act as nucleation sites for porosity formation. Most oxides were observed in the form of long branched strings. In some cases, bifilms were also reported in addition to SrO and MgO.

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The Analysis of Strontium Modification on Microstructure and Mechanical Properties of Al-25%Mg2Si In Situ Composite

Cited by 16 publications

References 14 publications

Role of Mg₂Si particles on mechanical, wear, and corrosion behaviors of friction stir welding of AA6061-T6 and Al-Mg₂Si composite

Role of Mg₂Si particles on mechanical, wear, and corrosion behaviors of friction stir welding of AA6061-T6 and Al-Mg₂Si composite

High Performance of T6‐Treated Al–15Mg₂Si–3Cu Composite Reinforced with Spherical Primary Mg₂Si after the Co‐Modification of Bi + Sr

A Review Study on the Main Sources of Porosity in Al‐Si Cast Alloys

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The Analysis of Strontium Modification on Microstructure and Mechanical Properties of Al-25%Mg2Si In Situ Composite

Cited by 16 publications

References 14 publications

Role of Mg2Si particles on mechanical, wear, and corrosion behaviors of friction stir welding of AA6061-T6 and Al-Mg2Si composite

Role of Mg2Si particles on mechanical, wear, and corrosion behaviors of friction stir welding of AA6061-T6 and Al-Mg2Si composite

High Performance of T6‐Treated Al–15Mg2Si–3Cu Composite Reinforced with Spherical Primary Mg2Si after the Co‐Modification of Bi + Sr

A Review Study on the Main Sources of Porosity in Al‐Si Cast Alloys

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Product

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About

Role of Mg₂Si particles on mechanical, wear, and corrosion behaviors of friction stir welding of AA6061-T6 and Al-Mg₂Si composite

Role of Mg₂Si particles on mechanical, wear, and corrosion behaviors of friction stir welding of AA6061-T6 and Al-Mg₂Si composite

High Performance of T6‐Treated Al–15Mg₂Si–3Cu Composite Reinforced with Spherical Primary Mg₂Si after the Co‐Modification of Bi + Sr