Grain refinement of hypoeutectic Al-7wt.%Si alloy induced by an Al–V–B master alloy

Zhang, Yunhu; Ye, C.Y.; Shen, Yu; Chang, Wang; StJohn, David H.; Zhai, Qijie

doi:10.1016/j.jallcom.2019.152022

Cited by 45 publications

(13 citation statements)

References 45 publications

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“…Recently, Al-Nb-B and Al-V-B have been proposed as an alternative grain refining addition to overcome the Si poisoning effect. It should be noted that, in the case of the Al-Nb-B grain refiner, the Al 3 Nb, NbB 2 , and NbB 3 particles are acting synergistically during solidification, 15,16 i.e., realizing the full potential of Nb and B, as compared to Al-V-B, in which only VB 2 particles are potent rather than Al 3 V. 17 Moreover, Nb-based master alloys have been found to be efficient over a wide range of compositions and solidification conditions. 18 However, despite that manifest impact, Al-Nb-B grain refiners have not yet been fully studied in industrially important DC casting followed by thermomechanical treatment.…”

Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Structure and Properties of Nb-B Inoculated Direct Chill Cast AA4032 Alloy Extruded from As-Cast and Homogenized Conditions

Barekar

Skalicky

Wang

et al. 2022

JOM

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Al-Si wrought piston alloys can lack properties due to inefficient grain refining. A novel Al-Nb-B grain refiner was introduced some time ago, but has still not been assessed in industry for wrought alloys. This paper describes the first trial of Al-Ni-B addition and its impact on the full-scale manufacturing, structure, and properties of the AA4032 products extruded with and without billet homogenization. It is shown that Nb-B inoculation gives opportunities not only to have a refined as-cast structure but also a more homogenous distribution of the solute. In contrast, homogenization drives nucleation and coarsening of the Mg2Si phase that is retained during further extrusion and heat treatment also affecting the precipitation and properties. It was observed that non-homogenized specimens perform better during machining and tensile testing compared to homogenized specimens. The results are supported by electron microscopy investigations of microstructure formation during different steps in downstream processing.

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Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Structure and Properties of Nb-B Inoculated Direct Chill Cast AA4032 Alloy Extruded from As-Cast and Homogenized Conditions

Barekar

Skalicky

Wang

et al. 2022

JOM

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“…Some of these issues may be addressed by metal casting techniques, where there have been recent advances on the filling of thin-walled molds 45 allowing good dimensional control 46 – 50 coupled with good microstructural control 51 – 53 . However, the main difficulties associated with casting techniques are frequently related to mold production 54 .…”

Section: Introductionmentioning

confidence: 99%

Macro-, meso- and microstructural characterization of metallic lattice structures manufactured by additive manufacturing assisted investment casting

Carneiro

Rawson

Puga

et al. 2021

Sci Rep

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Cellular materials are recognized for their high specific mechanical properties, making them desirable in ultra-lightweight applications. Periodic lattices have tunable properties and may be manufactured by metallic additive manufacturing (AM) techniques. However, AM can lead to issues with un-melted powder, macro/micro porosity, dimensional control and heterogeneous microstructures. This study overcomes these problems through a novel technique, combining additive manufacturing and investment casting to produce detailed investment cast lattice structures. Fused filament fabrication is used to fabricate a pattern used as the mold for the investment casting of aluminium A356 alloy into high-conformity thin-ribbed (~ 0.6 mm thickness) scaffolds. X-ray micro-computed tomography (CT) is used to characterize macro- and meso-scale defects. Optical and scanning electron (SEM) microscopies are used to characterize the microstructure of the cast structures. Slight dimensional (macroscale) variations originate from the 3D printing of the pattern. At the mesoscale, the casting process introduces very fine (~ 3 µm) porosity, along with small numbers of (~ 25 µm) gas entrapment defects in the horizontal struts. At a microstructural level, both the (~ 70 μm) globular/dendritic grains and secondary phases show no significant variations across the lattices. This method is a promising alternative means for producing highly detailed non-stochastic metallic cellular lattices and offers scope for further improvement through refinement of filament fabrication.

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“…The Al-Si-Mg alloys, which owe excellent casting characteristics including good fluidity and less solidification shrinkage [1,2], are broadly applied in casting industry [3][4][5]. However, in a normal casting process, the α-Al grains have coarse dendritic morphology, and the Si particles generally have acicular morphology and discontinuous distribution, which have detrimental influence on the strength and especially elongation of the aluminum alloys [6,7]. The chemical refinement and modification, which is achieved by adding small amount modifying elements (Ti, Sr, rare earth), is a useful method to refine the α-Al grains and improve the Si morphology, and therefore enhance the mechanical properties of alloys [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Effect of Cooling Rates on the Microstructure and Mechanical Property of La Modified Al7SiMg Alloys Processed by Gravity Die Casting and Semi-Solid Die Casting

Feng

et al. 2020

Metals

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Rare earth (RE) additions are capable of refining the α-Al phase as well as modifying the eutectic Si particles of alloys. The cooling rate in casting process should be carefully concerned when the Al-Si alloys are refined and modified by adding RE elements. In this study, the effect of cooling rates on the microstructure and mechanical properties of La modified Al-7.0Si-0.3Mg alloys was studied in gravity die casting and semi-solid die casting. It is found that in La modified Al-7.0Si-0.3Mg alloys, with increasing the cooling rate from 0.2 to 9 K/s in gravity die casting, the α-Al grains are greatly refined and the Si particles are modified to branching morphology, which evidently increases the UTS and elongation of alloys. In addition, when increasing the cooling rate from 30 to 130 K/s in semi-solid die casting, the α-Al grains are refined from 140 to 47 μm, and the Si particles are modified to fibrous morphology, which increases the UTS from 190 to 230 MPa and elongation from 10% to 11%. However, the 0.4 wt.% La addition results to La-rich phases formed in microstructure, which impairs the mechanical properties of Al-7.0Si-0.3Mg alloys in semi-solid die casting.

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Grain refinement of hypoeutectic Al-7wt.%Si alloy induced by an Al–V–B master alloy

Cited by 45 publications

References 45 publications

Comparative Analysis of Structure and Properties of Nb-B Inoculated Direct Chill Cast AA4032 Alloy Extruded from As-Cast and Homogenized Conditions

Comparative Analysis of Structure and Properties of Nb-B Inoculated Direct Chill Cast AA4032 Alloy Extruded from As-Cast and Homogenized Conditions

Macro-, meso- and microstructural characterization of metallic lattice structures manufactured by additive manufacturing assisted investment casting

Effect of Cooling Rates on the Microstructure and Mechanical Property of La Modified Al7SiMg Alloys Processed by Gravity Die Casting and Semi-Solid Die Casting

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