Effect of potent TiB2 addition levels and impurities on the grain refinement of Al

Zhou, Li; Gao, Feng; Peng, Guosheng; Alba-Baena, Noé

doi:10.1016/j.jallcom.2016.07.062

Cited by 33 publications

(13 citation statements)

References 12 publications

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“…Prior work [12,25,26,27] showed the distribution of a good grain refiner. It should have small particle sizes and no large agglomerates—the shape of the particles reflects the efficiency of the refiners.…”

Section: Discussionmentioning

confidence: 99%

The Influence of Inter-Cooling and Electromagnetic Stirring above Liquidus on the Formation of Primary Al3Zr and Grain Refinement in an Al-0.2%Zr Alloy

et al. 2018

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The nucleation and grain growth that occur during solidification have been extensively examined, but insight into the influence of an external field on the formation of heterogeneous crystal nuclei above the liquidus remains unclear in the peritectic refinement mechanism. In this work, we studied the effect of cooling rate above the liquidus on the formation of primary Al3Zr and grain refinement in Al-0.2%Zr alloys with inter-cooling annular electromagnetic stirring (IC-AEMS). The results show that the size and distribution of primary Al3Zr are greatly improved, and the morphology transformed from large plate/blocky shapes without IC-AEMS to small blocks with IC-AEMS. Meanwhile, above the liquidus, the addition of an Al-Zr master alloy to pure Al alone did little to enhance the refinement, but after IC-AEMS, the grains were refined dramatically. The refinement result seems to be explained by two hypotheses of pre-nucleation and explosive nucleation.

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Section: Discussionmentioning

confidence: 99%

The Influence of Inter-Cooling and Electromagnetic Stirring above Liquidus on the Formation of Primary Al3Zr and Grain Refinement in an Al-0.2%Zr Alloy

et al. 2018

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“…In actuality, the latent heat released by previously growing grains will cause an accelerated consumption of nucleation undercooling in the remaining melt, rendering the relatively smaller particles inefficient for nucleation, and then the percentage of effective particles will decrease. [10] Second, in the phase field simulation, to model heterogeneous nucleation from TiC particles, a free growth model was used. The value for the critical undercooling DT n from TiC was calculated from the particle size according to the hemispherical cap model.…”

Section: Constitutional Undercooling Dt C and Nucleated Grains From Each Heterogeneous Nuclei Radiusmentioning

confidence: 99%

“…Previous studies on grain refiners have mainly focused on cast aluminum alloys, [5][6][7] and a number of mature, commercially utilized grain refining solutions for aluminum alloys have been produced. [8][9][10] Other systems, such as titanium alloys, have few known potent heterogeneous nuclei; however, various studies on Ti6Al4V grain refiners have been conducted in recent years, and some effective grain refiners for Ti6Al4V have been identified, such as Nb, W, and La 2 O 3 . [11,12] TiC has also been found to be an effective grain refiner.…”

Section: Introductionmentioning

confidence: 99%

Effects of Solidification Conditions on Grain Refinement Capacity of TiC in Directionally Solidified Ti6Al4V Alloy

Date

Yamamoto

Watanabe

et al. 2021

Metall Mater Trans A

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In this study, the effects of solidification conditions on the grain refinement capacity of heterogeneous nuclei TiC in directionally solidified Ti6Al4V alloy were investigated using experimental and numerical approaches. Ti6Al4V powder with and without TiC particles in a Ti6Al4V sheath was melted and directionally solidified at various solidification rates via the floating zone melting method. In addition, by using the phase field method, the microstructural evolution of directionally solidified Ti6Al4V was simulated by varying the temperature gradient G and solidification rate V. As the solidification rate increased, the increment of the prior β grain number by TiC addition also increased. There are two reasons for this: first, the amount of residual potent heterogeneous nuclei TiC is larger. Second, the amount of TiC particles that can nucleate becomes larger. This is because increasing the constitutional undercooling ΔTc leads to the activation of a smaller radius of heterogeneous nuclei and a higher nucleation probability from each radius. At a cooling rate R higher than that in the floating zone melting experiment (R = 3 to 1000 K/s), the maximum degree of constitutional undercooling ΔTc,Max has a peak value, which suggests that constitutional undercooling ΔTc has a smaller contribution at higher cooling rates, such as those that occur during electron beam melting (EBM), including laser powder bed fusion (LPBF).

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“…To meet the growing demand for lightweight components in the automotive and aerospace sectors, many researchers have used LPBF to fabricate high-performance aluminium (Al) alloys and composites. A variety of Alalloys have been successfully printed using LPBF, including Al-Si [4], Al-Si-Mg [5,6], Scalmalloy [7,8], Al-Mn-Sc [9,10], Al-Mg-Si-Sc [11,12], Al-Cu [13,14] and Al-matrix composites [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Synchrotron Characterisation of Ultra-Fine Grain TiB2/Al-Cu Composite Fabricated by Laser Powder Bed Fusion

Cai

Duan

et al. 2021

Acta Metall. Sin. (Engl. Lett.)

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Isotropy in microstructure and mechanical properties remains a challenge for laser powder bed fusion (LPBF) processed materials due to the epitaxial growth and rapid cooling in LPBF. In this study, a high-strength TiB2/Al-Cu composite with random texture was successfully fabricated by laser powder bed fusion (LPBF) using pre-doped TiB2/Al-Cu composite powder. A series of advanced characterisation techniques, including synchrotron X-ray tomography, correlative focussed ion beam–scanning electron microscopy (FIB-SEM), scanning transmission electron microscopy (STEM), and synchrotron in situ X-ray diffraction, were applied to investigate the defects and microstructure of the as-fabricated TiB2/Al-Cu composite across multiple length scales. The study showed ultra-fine grains with an average grain size of about 0.86 μm, and a random texture was formed in the as-fabricated condition due to rapid solidification and the TiB2 particles promoting heterogeneous nucleation. The yield strength and total elongation of the as-fabricated composite were 317 MPa and 10%, respectively. The contributions of fine grains, solid solutions, dislocations, particles, and Guinier–Preston (GP) zones were calculated. Failure was found to be initiated from the largest lack-of-fusion pore, as revealed by in situ synchrotron tomography during tensile loading. In situ synchrotron diffraction was used to characterise the lattice strain evolution during tensile loading, providing important data for the development of crystal-plasticity models.

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Effect of potent TiB2 addition levels and impurities on the grain refinement of Al

Cited by 33 publications

References 12 publications

The Influence of Inter-Cooling and Electromagnetic Stirring above Liquidus on the Formation of Primary Al3Zr and Grain Refinement in an Al-0.2%Zr Alloy

The Influence of Inter-Cooling and Electromagnetic Stirring above Liquidus on the Formation of Primary Al3Zr and Grain Refinement in an Al-0.2%Zr Alloy

Effects of Solidification Conditions on Grain Refinement Capacity of TiC in Directionally Solidified Ti6Al4V Alloy

Synchrotron Characterisation of Ultra-Fine Grain TiB2/Al-Cu Composite Fabricated by Laser Powder Bed Fusion

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