Simulation of Microstructure during Laser Rapid Forming Solidification Based on Cellular Automaton

There are serious questions about the grain structure of metals after laser melting and the ways that it can be controlled. In this regard, the current paper explains the grain structure of metals after laser melting using a new model based on combination of 3D finite element (FE) and cellular automaton (CA) models validated by experimental observation. Competitive grain growth, relation between heat flows and grain orientation and the effect of laser scanning speed on final micro structure are discussed with details. Grains structure after laser melting is founded to be columnar with a tilt angle toward the direction of the laser movement. Furthermore, this investigation shows that the grain orientation is a function of conduction heat flux at molten pool boundary. Moreover, using the secondary laser heat source (SLHS) as a new approach to control the grain structure during the laser melting is presented. The results proved that the grain structure can be controlled and improved significantly using SLHS. Using SLHS, the grain orientation and uniformity can be change easily. In fact, this method can help us to produce materials with different local mechanical properties during laser processing according to their application requirements.

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“…The thermo-physical parameters used to determine v g are Δ H = 370 [kJ/kg], Γ = 2 × 10 −7 [K/m] 41 and a (@ 1650 °C) = 8.9 × 10 −6 [m 2 /s].…”

Section: Methodsmentioning

confidence: 99%

Determination and controlling of grain structure of metals after laser incidence: Theoretical approach

Dezfoli

Hwang

Huang

et al. 2017

Sci Rep

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“…Software embedded (nucleation and growth and heat transfer) models are used only. c) Four prominent studies namely by Zhou et al [207], Zhang et al [208], Zinoviev et al [205] and a group at Shenyang, China [80] [206], have been reported very recently using CAFE but these are based on modelling microstructure evolution in modified additive manufacturing (HDMR [207], LAMP [174] Journal of Encapsulation and Adsorption Sciences on 316L SS [208], 2D CAFE [205], Cladding [80] 2) No effort has been made to correlate the effect of edge-to-edge matching (E2EM) [223] [224] with direction of easy heat flow and crystallographic orientation (an effect that can be inherently used in additive manufacturing).…”

Section: Current State Of Art In Modelling and Simulation Of Additivementioning

confidence: 99%

“…[206]) processes. d) Few studies in the past have been conducted employing selective laser melting (SLM) using CAFE [80] [206] [219] [220], CAPF, CAFVM [221], modified CAFE [222] approaches but none have been carried out on BMGMC.…”

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confidence: 99%

Modelling and Simulation of Solidification Phenomena during Additive Manufacturing of Bulk Metallic Glass Matrix Composites (BMGMC)—A Brief Review and Introduction of Technique

Rafique¹

2018

JEAS

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Despite a wealth of experimental studies focused on determining and improving mechanical properties and development of fundamental understanding of underlying mechanisms behind nucleation and growth of ductile phase precipitates from melt in glassy matrix, still, there is dearth of knowledge about how these ductile phases nucleate during solidification. Various efforts have been made to address this problem such as experiments in microgravity, high resolution electron microscopy and observation in synchrotron light after levitation but none have proved out to be satisfactory. In this study, an effort has been made to address this problem by modelling and simulation. Current state of the art of development, manufacturing, characterisation and modelling and simulation of bulk metallic glass matrix composites is described in detail. Evolution of microstructure in bulk metallic glass matrix composites during solidification in additive manufacturing has been presented with the aim to address fundamental problem of evolution of solidification microstructure as a result of solute partitioning, diffusion and capillary action. An overview is also presented to explain the relation of microstructure evolution to hardness and fracture toughness. This is aimed at overcoming fundamental problem of lack of ductility and toughness in this diverse class of materials. Quantitative prediction of solidification microstructure is done with the help of advanced part scale modelling and simulation techniques. It has been systematically proposed that 2-dimensional cellular automaton (CA) method combined with finite element (for thermal modelling) tools (CA-FE) programmed on FORTRAN  and parallel simulated on ABAQUS  would best How to cite this paper: Rafique, M.M.A. (2018) Modelling and Simulation of Solidification Phenomena during Additive Manufacturing of Bulk Metallic Glass Matrix Composites (BMGMC)-A Brief Review

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“…No matter which initial state is chosen for a cellular automaton, their evolution exhibits properties of one of four classes. On account of the dynamical features of cellular automata, they have been used to model systems in biology [17,18], ecology [19,20], physics [21], and chemistry [22]. Urban systems, as well as land use, have been also application fields of cellular automata as it is shown in [23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Distributed Control of a Manufacturing System with One‐Dimensional Cellular Automata

et al. 2018

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We present a distributed control modeling approach for an automated manufacturing system based on the dynamics of one-dimensional cellular automata. This is inspired by the fact that both cellular automata and manufacturing systems are discrete dynamical systems where local interactions given among their elements (resources) can lead to complex dynamics, despite the simple rules governing such interactions. The cellular automaton model developed in this study focuses on two states of the resources of a manufacturing system, namely, busy or idle. However, the interaction among the resources such as whether they are shared at different stages of the manufacturing process determines the global dynamics of the system. A procedure is shown to obtain the local evolution rule of the automaton based on the relationships among the resources and the material flow through the manufacturing process. The resulting distributed control of the manufacturing system appears to be heterarchical, and the evolution of the cellular automaton exhibits a Class II behavior for some given disordered initial conditions.

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Simulation of Microstructure during Laser Rapid Forming Solidification Based on Cellular Automaton

Cited by 15 publications

References 9 publications

Determination and controlling of grain structure of metals after laser incidence: Theoretical approach

Determination and controlling of grain structure of metals after laser incidence: Theoretical approach

Modelling and Simulation of Solidification Phenomena during Additive Manufacturing of Bulk Metallic Glass Matrix Composites (BMGMC)—A Brief Review and Introduction of Technique

Distributed Control of a Manufacturing System with One‐Dimensional Cellular Automata

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