scholarly journals The Analytical Prediction of Thermal Distribution and Defect Generation of Inconel 718 by Selective Laser Melting

2020 ◽  
Vol 10 (20) ◽  
pp. 7300 ◽  
Author(s):  
Huadong Yang ◽  
Zhen Li ◽  
Siqi Wang
Keyword(s):  
Selective Laser Melting ◽  
Process Parameters ◽  
Analytical Method ◽  
Inconel 718 ◽  
Analytical Prediction ◽  
Generation Process ◽  
Laser Melting ◽  
Internal Defects ◽  
Defect Generation ◽  
Melt Pool

In selective laser melting, the rapid change of the temperature field caused by the rapid movement of the laser causes the instability of the melt pool flow, resulting in a generation of defects, such as lack of fusion, keyholing and balling effect, which greatly affect the performance of parts. In order to fully understand the temperature distribution and defect generation process of selective laser melting (SLM), experimental research, numerical simulation and analytical methods are mainly applied. The analytical method is suitable for the determination of the optimal process parameters because it is simple and consumes fewer resources. In a simulation, the absorptivity of the material is usually regarded as a constant, but experimental studies have shown that absorptivity is related to temperature, laser power, scanning speed, layer thickness and other process parameters. Considering the dynamics of thermal physical properties of Inconel 718, an improved analytical method was proposed and successfully applied to thermal analysis and the prediction of melt pool size. By comparing with the results of finite element simulation, experiment and other analytical solutions, the ease of use and effectiveness of the method are verified. Based on the prediction of the melt pool and the criterion of internal defects, the combination of process parameters that produce internal defects is calculated, which will make it possible to quickly obtain ideal process parameters.

Selective Laser Melting of the Inconel 718 Nickel Superalloy

2014 ◽  
Vol 698 ◽  
pp. 333-338 ◽  
Author(s):  
Vadim Sh. Sufiiarov ◽  
Evgenii V. Borisov ◽  
Igor A. Polozov
Keyword(s):  
Selective Laser Melting ◽  
Process Parameters ◽  
Inconel 718 ◽  
Melting Process ◽  
Nickel Superalloy ◽  
Mechanical Tests ◽  
Laser Melting ◽  
Influence Of Process Parameters ◽  
Inconel 718 Superalloy

The results of the research on selective laser melting process of the Inconel 718 superalloy powder under conditions of additive manufacturing of parts for special purposes are presented. The influence of process parameters on the quality of manufactured parts is shown. Process parameters which allow manufacturing parts with the density close to 100%, are determined. Also, the results of mechanical tests and investigation of microstructure are presented.

A Sensitivity Analysis Study on the Material Properties and Process Parameters for Selective Laser Melting of Inconel 625

2015 ◽  
Author(s):  
Luis E. Criales ◽  
Yiğit M. Arısoy ◽  
Tuğrul Özel
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Scanning Speed ◽  
Inconel 625 ◽  
Pool Data ◽  
Temperature Profiles ◽  
Laser Melting ◽  
Melt Pool ◽  
Laser Heat Source

A prediction of the 2-D temperature profile and melt pool geometry for Selective Laser Melting (SLM) of Inconel 625 metal powder with a numerically-based approach for solving the heat conduction-diffusion equation was established in this paper. A finite element method solution of the governing equation was developed. A review of the current efforts in numerical modeling for laser-based additive manufacturing is presented. Initially, two-dimensional (2-D) temperature profiles along the scanning (x-direction) and hatch direction (y-direction) are calculated for a moving laser heat source to understand the temperature rise due to heating during SLM. The effects of varying laser power, scanning speed and the powder material’s density are analyzed. Based on the predicted temperature distributions, melt pool geometry, i.e. the locations at which melting of the powder material occurs, is determined. The results are chiefly compared against the published literature on melt pool data. The main goal of this research is to develop a computational tool with which investigation of the importance of various laser, material, and process parameters on the built dimensional quality in laser-based additive manufacturing becomes not only possible but also practical and reproducible.

scholarly journals Selective Laser Melting of Pre-Alloyed NiTi Powder: Single-Track Study and FE Modeling with Heat Source Calibration

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7486
Author(s):  
Stanislav V. Chernyshikhin ◽  
Denis G. Firsov ◽  
Igor V. Shishkovsky
Keyword(s):  
Heat Source ◽  
Thermal Behavior ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Laser Power ◽  
Scanning Speed ◽  
Fe Modeling ◽  
Single Track ◽  
Laser Melting ◽  
Melt Pool

Unique functional properties such as the low stiffness, superelasticity, and biocompatibility of nickel–titanium shape-memory alloys provide many applications for such materials. Selective laser melting of NiTi enables low-cost customization of devices and the manufacturing of highly complex geometries without subsequent machining. However, the technology requires optimization of process parameters in order to guarantee high mass density and to avoid deterioration of functional properties. In this work, the melt pool geometry, surface morphology, formation mode, and thermal behavior were studied. Multiple combinations of laser power and scanning speed were used for single-track preparation from pre-alloyed NiTi powder on a nitinol substrate. The experimental results show the influence of laser power and scanning speed on the depth, width, and depth-to-width aspect ratio. Additionally, a transient 3D FE model was employed to predict thermal behavior in the melt pool for different regimes. In this paper, the coefficients for a volumetric double-ellipsoid heat source were calibrated with bound optimization by a quadratic approximation algorithm, the design of experiments technique, and experimentally obtained data. The results of the simulation reveal the necessary conditions of transition from conduction to keyhole mode welding. Finally, by combining experimental and FE modeling results, the optimal SLM process parameters were evaluated as P = 77 W, V = 400 mm/s, h = 70 μm, and t = 50 μm, without printing of 3D samples.

Melt pool simulation for the evaluation of process parameters in selective laser melting

2017 ◽  
Vol 14 ◽  
pp. 116-125 ◽  
Author(s):  
Thorsten Heeling ◽  
Michael Cloots ◽  
Konrad Wegener
Keyword(s):  
Selective Laser Melting ◽  
Process Parameters ◽  
Laser Melting ◽  
Melt Pool

scholarly journals A Computational Model of Melt Pool Morphology for Selective Laser Melting Process

2021 ◽  
Author(s):  
Kai Guo ◽  
Lihong Qiao ◽  
Zhicheng Huang ◽  
Nabil Anwer ◽  
Yuda Cao
Keyword(s):  
Computational Model ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Melting Process ◽  
Laser Melting ◽  
Synthetic Process ◽  
Part Geometry ◽  
Melt Pool ◽  
Proposed Model ◽  
High Consistency

Abstract Selective laser melting (SLM) is a promising metal additive manufacturing technology, which holds widespread applications in numerous fields. Unfortunately, it is arduous to predict the real SLM part geometry, which impedes its further development. While the morphology of melt pool, influenced and determined by process parameters, poses a crucial influence on the overall part geometry. Nonetheless, the association between process parameters and melt pool morphology is still unclear. Hence it is indispensable to explore relevant solution to address this issue. For this purpose, this paper proposes a new model to directly establish the mathematical relationship between process parameters and melt pool structure for SLM process. In this model, the status of melt pool is first qualitatively analyzed via the defined synthetic process index, and three types of melting states are differentiated including low melting, intermediate melting and high melting, which could cover different melt pool modes. Then, the computational model involving more physical mechanisms integrating mass conversion, heat exchange and temperature field is constructed. Melt pool critical geometries including the height, width, depth and length could be computed through the model. In order to validate the correctness of the proposed model, published experimental observations and existing models are compared. Calculation results from the proposed model show high consistency with the experimental samples and better accuracy than existing empirical models. Its applicability in melt pool classification and prediction is also verified, laying foundation for geometric simulation of SLM object which is successively shaped melt-pool by melt-pool.

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