scholarly journals Rapid solidification and surface topography for additive manufacturing with beam surface heating

2020 ◽  
Vol 28 ◽  
pp. 10-20 ◽  
Author(s):  
Jainagesh Akkaraju Sekhar
Keyword(s):  
Additive Manufacturing ◽  
Surface Topography ◽  
Rapid Solidification ◽  
Surface Heating ◽  
Beam Surface

scholarly journals Modelling of Microstructure Evolution during Laser Processing of Intermetallic Containing Ni-Al Alloys

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1051
Author(s):  
Mohammad Amin Jabbareh ◽  
Hamid Assadi
Keyword(s):  
Additive Manufacturing ◽  
Rapid Solidification ◽  
Microstructure Evolution ◽  
Phase Field ◽  
Laser Processing ◽  
Field Model ◽  
Phase Field Model ◽  
Intermetallic Phases ◽  
Al Alloy ◽  
Kinetic Effects

There is a growing interest in laser melting processes, e.g., for metal additive manufacturing. Modelling and numerical simulation can help to understand and control microstructure evolution in these processes. However, standard methods of microstructure simulation are generally not suited to model the kinetic effects associated with rapid solidification in laser processing, especially for material systems that contain intermetallic phases. In this paper, we present and employ a tailored phase-field model to demonstrate unique features of microstructure evolution in such systems. Initially, the problem of anomalous partitioning during rapid solidification of intermetallics is revisited using the tailored phase-field model, and the model predictions are assessed against the existing experimental data for the B2 phase in the Ni-Al binary system. The model is subsequently combined with a Potts model of grain growth to simulate laser processing of polycrystalline alloys containing intermetallic phases. Examples of simulations are presented for laser processing of a nickel-rich Ni-Al alloy, to demonstrate the application of the method in studying the effect of processing conditions on various microstructural features, such as distribution of intermetallic phases in the melt pool and the heat-affected zone. The computational framework used in this study is envisaged to provide additional insight into the evolution of microstructure in laser processing of industrially relevant materials, e.g., in laser welding or additive manufacturing of Ni-based superalloys.

Review on Phase-Field Modeling of Microstructure Evolutions: Application to Electron Beam Additive Manufacturing

2014 ◽  
Author(s):  
Seshadev Sahoo ◽  
Kevin Chou
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Rapid Solidification ◽  
Phase Field ◽  
Solidification Process ◽  
Materials Processing ◽  
Rapid Solidification Process ◽  
Phase Field Modeling ◽  
Diffuse Interfaces ◽  
Field Modeling

Powder-bed electron beam additive manufacturing (EBAM) is a relatively new technology to produce metallic parts in a layer by layer fashion by melting and fusing metallic powders. EBAM is a rapid solidification process and the properties of the parts depend on the solidification behavior as well as the microstructure of the build material. Thus, the prediction of part microstructures during the process may be an important factor for process optimization. Nowadays, the increase in computational power allows for direct simulations of microstructures during materials processing for specific manufacturing conditions. Among different methods, phase-field modeling (PFM) has recently emerged as a powerful computational technique for simulating microstructure evolutions at the mesoscale during a rapid solidification process. PFM describes microstructures using a set of conserved and non-conserved field variables and the evolution of the field variables are governed by Cahn-Hilliard and Allen-Cahn equations. By using the thermodynamics and kinetic parameters as input parameters in the model, PFM is able to simulate the evolution of complex microstructures during materials processing. The objective of this study is to achieve a thorough review of PFM techniques used in various processes, attempted for an application to microstructure evolutions during EBAM. The concept of diffuse interfaces, phase field variables, thermodynamic driving forces for microstructure evolutions and the kinetic phase-field equations are described in this paper.

scholarly journals In vitro cytotoxicity and surface topography evaluation of additive manufacturing titanium implant materials

2017 ◽  
Vol 28 (3) ◽  
Author(s):  
Jukka T. Tuomi ◽  
Roy V. Björkstrand ◽  
Mikael L. Pernu ◽  
Mika V. J. Salmi ◽  
Eero I. Huotilainen ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Surface Topography ◽  
Titanium Implant ◽  
In Vitro Cytotoxicity ◽  
Implant Materials

scholarly journals In Situ and Ex Situ Characterization of the Microstructure Formation in Ni-Cr-Si Alloys during Rapid Solidification—Toward Alloy Design for Laser Additive Manufacturing

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2192
Author(s):  
Xiaoshuang Li ◽  
Kai Zweiacker ◽  
Daniel Grolimund ◽  
Dario Ferreira Sanchez ◽  
Adriaan B. Spierings ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Chemical Composition ◽  
Laser Beam ◽  
Rapid Solidification ◽  
Liquid Droplet ◽  
Lamellar Microstructure ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
X Ray

Laser beam-based deposition methods such as laser cladding or additive manufacturing of metals promises improved properties, performance, and reliability of the materials and therefore rely heavily on understanding the relationship between chemical composition, rapid solidification processing conditions, and resulting microstructural features. In this work, the phase formation of four Ni-Cr-Si alloys was studied as a function of cooling rate and chemical composition using a liquid droplet rapid solidification technique. Post mortem x-ray diffraction, scanning electron microscopy, and in situ synchrotron microbeam X-ray diffraction shows the present and evolution of the rapidly solidified microstructures. Furthermore, the obtained results were compared to standard laser deposition tests. In situ microbeam diffraction revealed that due to rapid cooling and an increasing amount of Cr and Si, metastable high-temperature silicides remain in the final microstructure. Due to more sluggish interface kinetics of intermetallic compounds than that of disorder solid solution, an anomalous eutectic structure becomes dominant over the regular lamellar microstructure at high cooling rates. The rapid solidification experiments produced a microstructure similar to the one generated in laser coating thus confirming that this rapid solidification test allows a rapid pre-screening of alloys suitable for laser beam-based processing techniques.

Multiscale simulation of rapid solidification of an aluminium–silicon alloy under additive manufacturing conditions

2021 ◽  
Vol 48 ◽  
pp. 102353
Author(s):  
Patrick I. O’Toole ◽  
Milan J. Patel ◽  
Chao Tang ◽  
Dayalan Gunasegaram ◽  
Anthony B. Murphy ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Rapid Solidification ◽  
Multiscale Simulation ◽  
Silicon Alloy

Interplay between eutectic and dendritic growths dominated by Si content for Nb-Si-Ti alloys via rapid solidification

2021 ◽  
pp. 1-20
Author(s):  
Yueling Guo ◽  
Lina Jia ◽  
Junyang He ◽  
Siyuan Zhang ◽  
Zhiming Li ◽  
...  
Keyword(s):  
Electron Beam ◽  
Rapid Solidification ◽  
Atom Probe ◽  
Ti Alloys ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Beam Surface ◽  
Si Content ◽  
Design And Manufacture ◽  
Fully Lamellar

Abstract Rapid solidification techniques such as electron beam additive manufacturing are considered as promising pathways for manufacturing Nb-Si based alloys for ultra-high-temperature applications. Here we investigate the microstructure diversity of a series of Nb-Si-Ti alloys via electron beam surface melting (EBSM) to reveal their rapid solidification behaviors. Results show that the microstructural transition from coupled to divorced Nbss/Nb3Si eutectics can be triggered by increasing Si content. The formation of fully lamellar eutectics, evidenced by scanning transmission electron microscopy and atom probe tomography (APT), is achieved in the EBSM-processed Nb18Si20Ti alloy (at%), in contrast to the hypereutectic microstructures in arc-melted counterparts. The dendritic microstructures containing divorced eutectics are generated with a higher content of Si during rapid solidification. The transition from faceted to non-faceted growth of intermetallic Nb3Si occurs with the formation of primary Nb3Si dendrites. The interplay between eutectic and dendritic growths of silicides is discussed to provide insights for future alloy design and manufacture.

Experimental Study of Disruption of Columnar Grains During Rapid Solidification in Additive Manufacturing

JOM ◽  
2016 ◽  
Vol 68 (3) ◽  
pp. 842-849 ◽  
Author(s):  
Guha Manogharan ◽  
Bharat Yelamanchi ◽  
Ronald Aman ◽  
Zaynab Mahbooba
Keyword(s):  
Experimental Study ◽  
Additive Manufacturing ◽  
Rapid Solidification ◽  
Columnar Grains

Modeling porous structures with fractal rough topography based on triply periodic minimal surface for additive manufacturing

2017 ◽  
Vol 23 (2) ◽  
pp. 257-272 ◽  
Author(s):  
Zhijia Xu ◽  
Qinghui Wang ◽  
Jingrong Li
Keyword(s):  
Additive Manufacturing ◽  
Minimal Surface ◽  
Surface Topography ◽  
Porous Structures ◽  
Fractal Surface ◽  
Content Type ◽  
Periodic Minimal Surface ◽  
Triply Periodic ◽  
Fractal Parameters ◽  
Triply Periodic Minimal Surface

Purpose The purpose of this paper is to develop a general mathematic approach to model the microstructures of porous structures produced by additive manufacturing (AM), which will result in fractal surface topography and higher roughness that have greater influence on the performance of porous structures. Design/methodology/approach The overall shapes of pores were modeled by triply periodic minimal surface (TPMS), and the micro-roughness details attached to the overall pore shapes were represented by Weierstrass–Mandelbrot (W-M) fractal representation, which was integrated with TPMS along its normal vectors. An index roughly reflecting the irregularity of fractal TPMS was proposed, based on which the influence of the fractal parameters on the fractal TPMS was qualitatively analyzed. Two complex samples of real porous structures were given to demonstrate the feasibility of the model. Findings The fractal surface topography should not be neglected at a micro-scale level. In addition, a decrease in the fractal dimension Ds may exponentially make the topography rougher; an increase in the height-scaling parameter G may linearly increase the roughness; and the number of the superposed ridges has no distinct influence on the topography. Furthermore, the synthesis method is general for all implicit surfaces. Practical implications The method provides an alternative way to shift the posteriori design paradigm of porous media to priori design mode through numeric simulation. Therefore, the optimization of AM process parameters, as well as the porous structure, can be potentially realized according to specific functional requirement. Originality/value The synthesis of TPMS and W-M fractal geometry was accomplished efficiently and was general for all implicit freeform surfaces, and the influence of the fractal parameters on the fractal TPMS was analyzed more systematically.

scholarly journals Variation of Surface Topography in Laser Powder Bed Fusion Additive Manufacturing of Nickel Super Alloy 625

2019 ◽  
Vol 124 ◽  
Author(s):  
Jason C. Fox
Keyword(s):  
Additive Manufacturing ◽  
Surface Topography ◽  
Surface Texture ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Alloy 625 ◽  
Data Files ◽  
Height Data ◽  
Super Alloy

This document provides details on the files available for download in the dataset "Variation of Surface Texture in Laser Powder Bed Fusion of Nickel Super Alloy 625." The following sections provide details on the experiments, methods, and data files. The experiment detailed in this document methodically varies part position and surface orientation relative to the build plate and relative to the recoater blade. This dataset provides surface height data for analysis and development of correlations by the greater research.

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