The Formation Mechanism of Porosity for Spray-deposited 7075 Alloy

Cao, Fuyang; Li, Haichao; Ning, Zhiliang; Jia, Yandong; Gu, Xiaofeng; Lei, Yu; Liu, Zuyan; Sun, Jianfei

doi:10.1590/1516-1439.328414

Cited by 6 publications

(3 citation statements)

References 13 publications

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“…They form in the mushy zone, and their morphologies and extent are distinct. Morphology of gas porosity, resembles a spherical shape, while shrinkage porosity morphology is almost always irregular and elongated 3 .…”

Section: Introductionmentioning

confidence: 99%

Microstructural Patterns, Microsegregation, Porosity, and Mechanical Properties of Hypoeutectic Al-Fe Alloy, and its Dependency with Solidification Thermal Parameters

et al. 2022

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Al-Fe alloys are usually used as packaging and structural materials, but in the recent years, there have been considered for possible applications in aerospace field. The solidification sequence in pure aluminum containing 1 wt.% Fe is described in term of the formation of macrostructure, microstructure, microsegregation, porosity and mechanical properties. This material was studied in the upward unidirectional solidification system under transient heat flow conditions. Differences in microstructure, microsegregation, porosity and mechanical properties such as ultimate tensile strength, elongation and microhardness, due to the thermal parameter effects were observed and discussed. Experimental growth laws relating cellular spacing to the cooling rate and solidification speed have been determined, indicating that the increase in thermal parameter have induced a refinement effect on cell morphology. Microsegregation profiles of Fe solute were experimentally determined from the central region of the cell to the intercellular region under different solidification speeds. The Fe microsegregation determined from central region of the cell (F S = 0) to the intercellular region (F S = 1) show a growing profile, in any case considered. However, the profiles move upward with the increase in solidification speed, which indicates that Fe solubility in solid, increases with the increase in solidification speed. The effect of the solidification thermal parameters and cellular spacing on the porosity content were experimentally investigated. The value of porosity content increased along the casting. These results have pointed out that porosity content is affected by solidification parameters and cellular patterns. Further, measurable effects of the thermal parameters, cellular spacing and porosity content on the mechanical properties were experimentally determined. It stands out among experimental results the influence of porosity on the mechanical properties of as-cast material. In any case analyzed, mechanical properties increase with decreasing porosity content.

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Section: Introductionmentioning

confidence: 99%

Microstructural Patterns, Microsegregation, Porosity, and Mechanical Properties of Hypoeutectic Al-Fe Alloy, and its Dependency with Solidification Thermal Parameters

et al. 2022

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“…Spray forming technique one hand could systematically enhance the mechanical properties including strength, plasticity, and toughness by combination with densification process such as hot isostatic pressing (HIP) and on the other hand is applicable to wide spectrum of metal materials including aluminum alloys, magnesium alloys, titanium alloys and high‐temperature alloys; thus, it has been utilized to manufacture various key components in fields such as aerospace, vessels, and automobile 4,5 . It was shown that the impaction between droplet and deposited layer and the droplet deformation critically affect the deposition structure evolution; therefore, they should be precisely controlled and optimized through spray deposition processes optimization 6–8 . In fact, the impaction behaviors of high‐speed liquid droplet must be carefully investigated also in many other industry technologies such as spray cooling 9 and thermal spraying 10 …”

Section: Introductionmentioning

confidence: 99%

Preliminary study on deformation behaviors of spray droplet impacting on nonrigid deposited layer

Cao

Lei

Zhang

et al. 2021

Mat Design & Process Comms

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Spray forming technology has been adopted to prepare essential castings in various industry fields. Understanding what happen during the impaction of droplet on deposited layer is critical to optimize spray forming processes and so improve the final casting quality. The present work investigated the morphology evolution of droplet and deposited layer during impaction, with particularly emphasis on the nonrigid feature of deposited layer in practical spray forming. The results demonstrate that the deposited layer would suffer obvious deformation under the impaction of flighting droplet, which produce puddle‐like structure on the deposited layer. The droplet spreading process would be suppressed by this puddle‐like structure when the droplet temperature is not high enough, which might introduce gap between the droplet and the deposited layer, so might cause tiny holes in the final casting. Moreover, the simulation results suggest that multiple droplet impaction might cause column structure on the deposited layer, this would seriously increase the surface roughness of the final casting. The investigations hint that the mechanical properties of deposited layer should be considered when studying the microstructure evolution and mechanism of spray forming casting.

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“…During the last decade Cold Gas Dynamic Spray (hereinafter called CGDS or simply Cold Spray) has been the object of great interest from both research community and industry, with several research papers, patents, and books published on this topic 1,2 . Nowadays cold spray is no more an experimental technology confined to the laboratory but has proven its ability to compete in the commercial field with older technologies, with special regards to the production of metallic coatings and the repair of damaged components 3,4 .…”

Section: Introductionmentioning

confidence: 99%

Repairing of an Engine Block Through the Cold Gas Dynamic Spray Technology

Astarita¹,

Coticelli²,

Prisco³

2016

Mat. Res.

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In the modern automotive industry, the maintenance of the vehicle during its life cycle is increasing in importance due to both economical and environmental considerations. A new frontier is the reparation of large parts, originally made by fusion, by the addition of material. The standard technique in the field is the use of TIG welding, but in the last few years Cold Dynamic Gas Spray (CDGS) has started to show many promises in supplanting TIG repairs. The main advantage of CDGS is the absence of thermal stresses in the repaired zone with the elimination of thermal distension treatment of the part. In this paper we study the use of CDGS to repair wear damage on a commercial aluminium engine block in comparison with the standard repair procedure with TIG. The result obtained shows that CDGS is an effective technology for industrial-level repair.

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The Formation Mechanism of Porosity for Spray-deposited 7075 Alloy

Cited by 6 publications

References 13 publications

Microstructural Patterns, Microsegregation, Porosity, and Mechanical Properties of Hypoeutectic Al-Fe Alloy, and its Dependency with Solidification Thermal Parameters

Microstructural Patterns, Microsegregation, Porosity, and Mechanical Properties of Hypoeutectic Al-Fe Alloy, and its Dependency with Solidification Thermal Parameters

Preliminary study on deformation behaviors of spray droplet impacting on nonrigid deposited layer

Repairing of an Engine Block Through the Cold Gas Dynamic Spray Technology

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