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Spray forming

About: Spray forming is a research topic. Over the lifetime, 1153 publications have been published within this topic receiving 12869 citations. The topic is also known as: spray casting & spray deposition.


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Journal ArticleDOI
TL;DR: In this paper, a concise but thorough compilation of melt disintegration phenomenology is provided, with emphasis on high pressure gas atomisation, inclusive of notation on mean particle diameters, the role of viscosity, density and other dimensionless ratios that enter as variables in highpressure gas atomization and spray forming, as well as break up of a liquid column and theories of drop disintegration in flight.
Abstract: Gas atomisation phenomenology of liquid metals and alloys is both intriguing and instructive. Predating atomistic studies of melt disintegration by almost three decades, it provides a functional means of correlation between drop sizes and processing parameters, as is the case in liquid metal spray forming. In this article a concise but thorough compilation of melt disintegration phenomenology is provided, with emphasis on high pressure gas atomisation, inclusive of notation on mean particle diameters, the role of viscosity, density and other dimensionless ratios that enter as variables in high pressure gas atomization and spray forming, as well as break up of a liquid column and theories of drop disintegration in flight. The article concludes by introducing the very efficient Surface Wave Formation principle which facilitates the treatment of complex atomisation geometries and turbulent regimes.

27 citations

Journal ArticleDOI
TL;DR: A review of the state-of-the-art in modeling liquid chemical precursor droplets and particles injected into high-temperature jets in the form of DC-arc plasmas and high-velocity oxy-fuel flames to form coatings is presented in this article.
Abstract: This article presents a review of the current state-of-the-art in modeling of liquid chemical precursor droplets and particles injected into high-temperature jets in the form of DC-arc plasmas and high-velocity oxy-fuel flames to form coatings. Conventional thermal spray processes have typically utilized powders that are melted and deposited as a coating on hardware surfaces. However, production of coatings utilizing liquid precursors has emerged in the last decade as a viable alternative to powder deposition. Use of liquid precursors has advantages over powder in terms of their relative ease of feeding and tailoring of chemical compositions. In this article, we review the modeling approaches to injection of liquid precursors and particles into plasmas and high-velocity oxy-fuel flames. Modeling approaches for the high-temperature DC-arc plasma and oxy-fuel flame jets are first reviewed. This is followed by the liquid spray and droplet level models of the liquid precursors injected into these high-temperature jets. The various knowledge gaps in detailed modeling are identified and possible research directions are suggested in certain areas.

27 citations

Journal ArticleDOI
TL;DR: In this paper, the complex equations governing droplet dynamic and thermal behaviour during spray forming have been analyzed to give an approximate expression for the spray solid fraction as a function of the process parameters of the form f S = a 1 + a 2 Δ T + a 3 υ g i z 2 / 3 M ˙ 1 / 2 where vgi is the initial gas velocity at atomisation, Ṁ is the molten alloy mass flow rate, ΔT is the super heat above the liquidus, and z is the axial distance.
Abstract: The complex equations governing droplet dynamic and thermal behaviour during spray forming have been analysed to give an approximate expression for the spray solid fraction as a function of the process parameters of the form f S = a 1 + a 2 Δ T + a 3 υ g i z 2 / 3 M ˙ 1 / 2 where vgi is the initial gas velocity at atomisation, Ṁ is the molten alloy mass flow rate, ΔT is the molten alloy super heat above the liquidus, and z is the axial distance. This expression provides an extremely convenient relationship to indicate the variation of spray solid fraction during spray forming, which is a key variable controlling final as sprayed billet microstructure. Predicted N2 atomised Al-4 wt%Cu spray solid fractions based upon the analytical expression have been compared with equivalent results obtained from a detailed computer model described previously in Parts I and II under a wide range of conditions of vgi, Ṁ, ΔT and z and gave good agreement. Best-fit values of a1, a2 and a3 were 1.9 × 10−1, −1.4 × 10−3 and 1.3 × 10−3 respectively, in good agreement with predicted values.

27 citations

Journal ArticleDOI
TL;DR: In this article, an optical sensing device based on the principle of high-speed pyrometry, developed for on-line monitoring of particle temperature, velocity and diameter of in-flight particles during thermal spraying conditions (eg plasma guns), is for the first time applied and examined in the spray forming process Thermal radiation emitted by the particles is collected by a sensing head attached to the spray cone and transmitted through optical fibers to a detection cabinet located away from the dusty environment.
Abstract: The structure and material properties of spray formed products depend directly on the thermal state of particles before they impact the substrate or on the already deposited layer Monitoring particle temperature, velocity and size can thus provide a unique tool for optimizing the material properties as well as controlling spraying conditions during deposition In this paper, an optical sensing device based on the principle of high-speed pyrometry, developed for on-line monitoring of particle temperature, velocity and diameter of in-flight particles during thermal spraying conditions (eg plasma guns), is for the first time applied and examined in the spray forming process Thermal radiation emitted by the particles is collected by a sensing head attached to the spray cone and transmitted through optical fibers to a detection cabinet located away from the dusty environment Tests were carried out with different materials, spray pressures and measurement positions to exhibit the efficiency of the measurement system in the spray forming process

27 citations

Journal ArticleDOI
TL;DR: In this article, the influence of spray deposition process on the refinement of silicon phase and the tribological performance of hyper-eutectic Al-Si alloys is reported.

27 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202310
202216
202117
202037
201933
201826