The formation mechanism of Al<sub>6</sub>(Fe, Mn) in die-cast Al–Mg alloys

Zhu, Xiangzhen; Blake, Paul; Ji, Shouxun

doi:10.1039/c8ce00675j

Cited by 16 publications

(9 citation statements)

References 32 publications

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“…Therefore, heat treatment process is normally not preferred on HPDC castings. In recent years, Lumley [32,33], Ji [6,18,28,34] and Cecchel [34] confirmed that HPDC components can be successfully heat treated without causing significant surface blistering or distortion if the solution treatment is carried out at lower temperatures (e.g. 440°C to 490°C for Al-Si-Mg alloys) than normal temperatures.…”

Section: Relationship Between Microstructure and Mechanical Propertiesmentioning

confidence: 95%

“…With the significant progress of HPDC technology derived by increased requirements in the past decades, the development and application of new alloys with excellent properties are considered as an important way to offer high-quality castings [16]. Recently, a high-strength Al-Mg-Fe-Mn alloy was developed for high-pressure die casting [17,18], achieving the ultimate tensile strength of [ 300 MPa, the yield strength of about [ 150 MPa and the tensile elongation of [ 10% under as-cast condition. Moreover, the application of conventional detrimental Fe and Mn elements to form intermetallic for strengthening can successfully increase the yield strength of alloys.…”

Section: Introductionmentioning

confidence: 99%

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The development of low-temperature heat-treatable high-pressure die-cast Al–Mg–Fe–Mn alloys with Zn

et al. 2021

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In the present work, a novel low-temperature heat-treatable recycled die-cast Al–Mg alloy was developed by adding Zn into non-heat-treatable Al–5Mg–1.5Fe–0.5Mn alloy. The results showed that Zn additions resulted in the formation of equilibrium phase T-Mg32(Al, Zn)49 under as-cast condition, which can be dissolved into the α-Al matrix at a relatively low solution temperature (430 °C) and thus set the base for the low-temperature heat treatment. The mechanical test results indicated that Zn additions had a smooth liner improvement in the strength of all as-cast alloys and T6-state alloys with 1% and 2% Zn as its concentration increased but resulted in a sharp improvement on the strength of T6-state alloy when Zn concentration increased from 2 to 3%. TEM analysis revealed that the precipitate in T6-state Al–5Mg–1.5Fe–0.5Mn–3Zn alloy is η′ phase, rather than the widely reported T″ or T′ phase in other Al–Mg–Zn alloys with approximately same Mg and Zn concentrations. After the optimized low-temperature T6 heat treatment (solution at 430 °C for 60 min and ageing at 120 °C for 16 h), the Al–5Mg–1.5Fe–0.5Mn–3Zn alloy exhibits the yield strength of 321 MPa, ultimate tensile strength of 445 MPa and elongation of 6.2%.

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Section: Relationship Between Microstructure and Mechanical Propertiesmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

The development of low-temperature heat-treatable high-pressure die-cast Al–Mg–Fe–Mn alloys with Zn

et al. 2021

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“…Thus, the strengthening effect of Al–AlFe eutectic structure is also unaffected. Ji and co‐workers [ 16 ] reported the strengthening effect of high‐pressure die‐cast Al–Mg alloys with added Fe. Upon increasing the Fe level (0.5–3.5 wt%), the yield strength increased, and the elongation decreased.…”

Section: Introductionmentioning

confidence: 99%

New Strategy to Improve the Mechanical Properties in Cast Al–Mg–Fe Alloys by the Formation of Al–AlFe Eutectic

et al. 2021

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Fe-containing intermetallics are often detrimental to the mechanical properties in aluminum alloy. However, an Al-Fe alloy system can form an Al þ AlFe eutectic structure in a narrow freezing range, providing the fine Al 13 Fe 4 or Al 6 Fe intermetallics. Herein, the ternary Al-Mg-Fe alloy is selected to achieve the Al þ AlFe eutectic structure composition and form fine AlFe intermetallics for improving the strength and ductility of Al-Mg cast alloy. The results show that as the composition of Al-Mg-Fe alloy is closer to the Al þ AlFe eutectic composition, the amount of coarse Al 13 Fe 4 intermetallics decreases, whereas the amount of fine Al þ Al 13 Fe 4 eutectic increases. The microstructural evolution results in the improvement of yield strength (72.8-92.4 MPa), tensile strength (126.1-213.7 MPa), and the elongation (2.5-6.2%). This work provides a new strategy to improve the mechanical properties in Al-Mg cast alloy.

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“…Table 1 summarizes the Al–Fe IMCs formed in different processes reported in the literature. The metastable, ductile Al 6 Fe was observed in the processes of direct chill casting (example #1 in Table 1 ) 10 , high-pressure die casting (#2) 13 , equal channel angular extrusion (#3) 14 , tungsten inert gas (TIG) welding-brazing (#4) 15 , and additive manufacturing (AM) via laser powder bed fusion (#5) 16 . These observations suggest that Al 6 Fe is an IMC existing at high pressures.…”

Section: Introductionmentioning

confidence: 99%

Forming mechanism of equilibrium and non-equilibrium metallurgical phases in dissimilar aluminum/steel (Al–Fe) joints

Shang

Sun

Pan

et al. 2021

Sci Rep

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Forming metallurgical phases has a critical impact on the performance of dissimilar materials joints. Here, we shed light on the forming mechanism of equilibrium and non-equilibrium intermetallic compounds (IMCs) in dissimilar aluminum/steel joints with respect to processing history (e.g., the pressure and temperature profiles) and chemical composition, where the knowledge of free energy and atomic diffusion in the Al–Fe system was taken from first-principles phonon calculations and data available in the literature. We found that the metastable and ductile (judged by the presently predicted elastic constants) Al6Fe is a pressure (P) favored IMC observed in processes involving high pressures. The MoSi2-type Al2Fe is brittle and a strong P-favored IMC observed at high pressures. The stable, brittle η-Al5Fe2 is the most observed IMC (followed by θ-Al13Fe4) in almost all processes, such as fusion/solid-state welding and additive manufacturing (AM), since η-Al5Fe2 is temperature-favored, possessing high thermodynamic driving force of formation and the fastest atomic diffusivity among all Al–Fe IMCs. Notably, the ductile AlFe3, the less ductile AlFe, and most of the other IMCs can be formed during AM, making AM a superior process to achieve desired IMCs in dissimilar materials. In addition, the unknown configurations of Al2Fe and Al5Fe2 were also examined by machine learning based datamining together with first-principles verifications and structure predictions. All the IMCs that are not P-favored can be identified using the conventional equilibrium phase diagram and the Scheil-Gulliver non-equilibrium simulations.

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The formation mechanism of Al₆(Fe, Mn) in die-cast Al–Mg alloys

Abstract: The equilibrium morphology of Al6(Fe, Mn) is a rhombic prism covered by {110} and {002} faces. Due to the limitation of volume-diffusion, the larger primary Al6(Fe, Mn) has a hollow inside, and the small eutectic Al6(Fe, Mn) is solid.

Cited by 16 publications

References 32 publications

The development of low-temperature heat-treatable high-pressure die-cast Al–Mg–Fe–Mn alloys with Zn

The development of low-temperature heat-treatable high-pressure die-cast Al–Mg–Fe–Mn alloys with Zn

New Strategy to Improve the Mechanical Properties in Cast Al–Mg–Fe Alloys by the Formation of Al–AlFe Eutectic

Forming mechanism of equilibrium and non-equilibrium metallurgical phases in dissimilar aluminum/steel (Al–Fe) joints

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The formation mechanism of Al6(Fe, Mn) in die-cast Al–Mg alloys

Abstract: The equilibrium morphology of Al6(Fe, Mn) is a rhombic prism covered by {110} and {002} faces. Due to the limitation of volume-diffusion, the larger primary Al6(Fe, Mn) has a hollow inside, and the small eutectic Al6(Fe, Mn) is solid.

Cited by 16 publications

References 32 publications

The development of low-temperature heat-treatable high-pressure die-cast Al–Mg–Fe–Mn alloys with Zn

The development of low-temperature heat-treatable high-pressure die-cast Al–Mg–Fe–Mn alloys with Zn

New Strategy to Improve the Mechanical Properties in Cast Al–Mg–Fe Alloys by the Formation of Al–AlFe Eutectic

Forming mechanism of equilibrium and non-equilibrium metallurgical phases in dissimilar aluminum/steel (Al–Fe) joints

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The formation mechanism of Al₆(Fe, Mn) in die-cast Al–Mg alloys