Duplex Nucleation and Its Effect on the Grain Size and Properties of Near Eutectic Al-Si Alloys

Li, Wenbo; Wu, Yuying; Wu, Yongjie; Li, Yang; Ehti, Amanisha; Liu, Xiangfa

doi:10.3390/ma15072507

Cited by 2 publications

(1 citation statement)

References 31 publications

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“…For example, the addition of hafnium (Hf) reduces the solid solution temperature and is hence advantageous in lowering manufacturing costs at an industrial scale [20,21]. Similarly, the addition of Al induces a grain refinement effect, which is beneficial in enhancing IMC hardness [22,23]. The addition of Nb as a doping element has attracted particular attention due to its effects in enhancing the yield strength through the formation of ultrafine grains, good corrosion resistance at high temperature, and high dislocation density [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties and Microstructural Evolution of TiNi-Based Intermetallic Alloy with Nb Addition

2022

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TiNi intermetallic alloys were prepared with 2, 4 and 6 at.% niobium (Nb) addition. The mechanical properties and microstructures of the alloys were investigated under both static (1 × 10−1 to 1 × 10−3 s−1) and dynamic (4 × 103 to 6 × 103 s−1) loading conditions. The intermetallic alloy structures and surface morphologies of the alloys were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. In addition, the fracture morphologies were observed by optical microscopy (OM). It was shown that the addition of 2 to 4 at.% Nb increased the strength of the TiNi alloy. However, as the level of Nb addition was further increased to 6 at.%, a significant reduction in strength occurred. For a constant Nb addition, the plastic flow stress and strain rate sensitivity increased with increasing strain rate under both loading conditions (static and dynamic). The XRD and SEM results showed that the original surface morphologies were composed primarily of dendritic structures and fine β-Nb + TiNi eutectic systems. Moreover, the OM results showed that the alloys underwent a transition from a brittle fracture mode to a ductile fracture mode as the level of Nb addition increased.

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Section: Introductionmentioning

confidence: 99%

Mechanical Properties and Microstructural Evolution of TiNi-Based Intermetallic Alloy with Nb Addition

2022

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Optimizing the Morphology and Solidification Behavior of Fe-Rich Phases in Eutectic Al-Si-Based Alloys with Different Fe Contents by Adding Mn Elements

Luo,

Tang,

Liang

et al. 2024

Materials

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A high Fe content easily produces Fe-rich phases with a harmful morphology, resulting in a huge detrimental effect on the properties and recycling ability of Al-Si alloys. Therefore, finding ways to effectively transform Fe-rich phases to form a beneficial phase or shape is of great significance. Accordingly, Al-Si-based alloys with Fe contents ranging from 0.1 wt.% to 2.0 wt.% were modified by different Mn additions. Moreover, experiments combined with simulations were utilized to comprehensively analyze the mechanism of Mn on the morphology and microstructural evolution of Fe-rich phases from different perspectives. The current findings determine that adding different Fe contents changes the phase-transition reactions in alloys. Without Mn, and by increasing the Fe content from 0.1 wt.% to 2.0 wt.%, the Fe-rich phases gradually convert from a skeleton-shaped α-Al8Fe2Si (<0.25 wt.%) to β-Al9Fe2Si2 with a fibrous (0.5 wt.%), needle-like (1.0 wt.%) and plate-like shape without curvatures (2.0 wt.%). The maximum length and mean aspect ratio increase from 12.01 μm to 655.66 μm and from 1.96 to 84.05, while the mean curvature decreases from 8.66 × 10−2 μm−1 to 8.25 × 10−4 μm−1. The addition of 0.35 wt.% Mn promotes a new Chinese-character and petal-shaped α-Al15(FeMn)3Si2, with an atomic ratio of Fe and Mn of 1:1 when the Fe content is lower than 0.5 wt.%, while it transforms to β-Al15(FeMn)3Si2 with an atomic ratio of 5:1, presenting as a refined plate-like shape with a certain curvature, as the Fe content increases to 2.0 wt.%. Mn alters the phase reactions and increases the threshold of the Fe content required for β-Al15(FeMn)3Si2, limiting the formation and growth of them simultaneously in time and space. The enrichment of Mn atoms and solute diffusion at the growth front of β-Al15(FeMn)3Si2, as well as the strong atomic-binding ability, can deflect the growth direction of β-Al15(FeMn)3Si2 for it to have a certain curvature. Additionally, the enriched Mn atoms easily form α-Al15(FeMn)3Si2 and cause the long β-Al15(FeMn)3Si2 to be broken and refined to further reduce the damages caused to the alloy’s performance. Ultimately, the maximum length and mean aspect ratio can be effectively reduced to 46.2% and 42.0%, respectively, while the mean curvature can be noticeably increased by 3.27 times with the addition of Mn.

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Duplex Nucleation and Its Effect on the Grain Size and Properties of Near Eutectic Al-Si Alloys

Cited by 2 publications

References 31 publications

Mechanical Properties and Microstructural Evolution of TiNi-Based Intermetallic Alloy with Nb Addition

Mechanical Properties and Microstructural Evolution of TiNi-Based Intermetallic Alloy with Nb Addition

Optimizing the Morphology and Solidification Behavior of Fe-Rich Phases in Eutectic Al-Si-Based Alloys with Different Fe Contents by Adding Mn Elements

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