Search Results - "Nastac, Laurentiu"

3D Modeling of the Solidification Structure Evolution and of the Inter Layer/Track Voids Formation in Metallic Alloys Processed by Powder Bed Fusion Additive Manufacturing by Nastac, Laurentiu

“…A fully transient discrete-source 3D Additive Manufacturing (AM) process model was coupled with a 3D stochastic solidification structure model to simulate the…”
Get full text

3D Modeling of the Solidification Structure Evolution of Superalloys in Powder Bed Fusion Additive Manufacturing Processes by Nastac, Laurentiu

“…Recently, a few computational methodologies and algorithms have been developed to simulate the microstructure evolution in powder bed fusion (PBF) additive…”
Get full text

Mathematical Modeling of the Solidification Structure Evolution in the Presence of Ultrasonic Stirring by Nastac, Laurentiu

“…Ultrasonic treatment (UST) was studied in this work to improve the quality of the cast ingots as well as to control the solidification structure evolution…”
Get full text

Mathematical Investigation of Fluid Flow, Mass Transfer, and Slag-steel Interfacial Behavior in Gas-stirred Ladles by Cao, Qing, Nastac, Laurentiu

“…In this study, the Euler-Euler and Euler-Lagrange modeling approaches were applied to simulate the multiphase flow in the water model and gas-stirred ladle…”
Get full text

Mathematical Modeling of the Multiphase Flow and Mixing Phenomena in a Gas-Stirred Ladle: The Effect of Bubble Expansion by Cao, Qing, Nastac, Laurentiu

“…A three-dimensional discrete phase model–volume of fluid coupled model has been developed to study the argon/steel/slag/air multiphase flow and mixing…”
Get full text

Numerical Modeling of Fluid Flow and Solidification Characteristics of Ultrasonically Processed A356 Alloys by Nastac, Laurentiu

“…The main objectives of this study is to determine the fluid flow characteristics and cavitation phenomena during molten A356 alloys processed via high power…”
Get full text

Prediction of Secondary Dendrite Arm Spacing in Al Alloys Using Machine Learning by Dong, Aqi, Nastac, Laurentiu

“…In this study, three machine learning (ML) models were developed to predict the secondary dendrite arm spacing (SDAS) and then predictions were validated…”
Get full text

Numerical Modeling of Carbide Redistribution during Centrifugal Casting of HSS Shell Rolls by Nastac, Laurentiu

“…A numerical model was further developed and applied in this work to understand and optimize the carbide redistribution during centrifugal casting process used…”
Get full text

Evaluation and Implementation of a Fundamental Model for Interfacial Heat Transfer Coefficient in High-Pressure Die-Casting by Karkkainen, Mikko, Nastac, Laurentiu

“…In the present study, the fundamental model for interfacial heat transfer coefficient (IHTC) in high-pressure die-casting (HPDC) developed by Hamasaiid et al …”
Get full text

CFD Modeling of Macro-segregation and Shrinkage During Solidification of Superalloy Castings by Nastac, Laurentiu

“…Minimizing macro-segregation during static casting of segregation prone alloys has always been a challenge. Over the years, alloy manufacturers have optimized…”
Get full text

Numerical Investigation of Desulfurization Kinetics in Gas-Stirred Ladles by a Quick Modeling Analysis Approach by Cao, Qing, Nastac, Laurentiu, Pitts-Baggett, April, Yu, Qiulin

“…A quick modeling analysis approach for predicting the slag-steel reaction and desulfurization kinetics in argon gas-stirred ladles has been developed in this…”
Get full text

Numerical modeling of the dispersion of ceramic nanoparticles during ultrasonic processing of aluminum-based nanocomposites by Zhang, Daojie, Nastac, Laurentiu

“…The metal–matrix-nano-composites (MMNCs) in this study consist of a 6061 alloy matrix reinforced with 1.0wt.% SiC nanoparticles that are dispersed within the…”
Get full text

Computational Fluid Dynamics Modeling of Macrosegregation and Shrinkage in Large-Diameter Steel Roll Castings by Nastac, Laurentiu

“…Minimizing macrosegregation and shrinkage in large cast steel mill rolls challenges the limits of commercial foundry technology. Processing improvements have…”
Get full text

Numerical Modeling of Macrosegregation in Binary Alloys Solidifying in the Presence of Electromagnetic Stirring by Poole, Gregory Michael, Heyen, Matthew, Nastac, Laurentiu, El-Kaddah, Nagy

“…A model for predicting solidification and solute segregation of binary alloys undergoing electromagnetic stirring has been developed. A dual-zone formulation…”
Get full text

Processing and Microstructure Characteristics of As-Cast A356 Alloys Manufactured via Ultrasonic Cavitation during Solidification by Xuan Yang, Jia Shian, Nastac Laurentiu

“…Recent studies have showed that the microstructure and mechanical properties of A356 alloy can be significantly improved when ultrasonic cavitation and…”
Get full text

The role of ultrasonic cavitation in refining the microstructure of aluminum based nanocomposites during the solidification process by Xuan, Yang, Nastac, Laurentiu

“…•An ultrasonic cavitation method applied during the solidification of nanocomposites is proposed.•Ultrasonic cavitation changed the microstructure from coarse…”
Get full text

Numerical Modeling of Convective Heat Transfer for Turbulent Flow in “Bubbler” Cooling Channels by Karkkainen, Mikko, Nastac, Laurentiu

“…In the present study, a numerical model was developed to investigate the heat transfer effect of single-phase turbulent flow in a “bubbler” geometry, typical…”
Get full text

A Multiscale Transient Modeling Approach for Predicting the Solidification Structure in VAR-Processed Alloy 718 Ingots by Nastac, Laurentiu

“…This paper describes the development and validation of a comprehensive multiscale modeling approach capable of predicting at the mesoscopic scale level the…”
Get full text

Progress on Numerical Modeling of the Dispersion of Ceramic Nanoparticles During Ultrasonic Processing and Solidification of Al-Based Nanocomposites by Zhang, Daojie, Nastac, Laurentiu

“…In present study, 6061- and A356-based nano-composites are fabricated by using the ultrasonic stirring technology (UST) in a coreless induction furnace. SiC…”
Get full text

Analytical modeling of solute redistribution during the initial unsteady unidirectional solidification of binary dilute alloys by Nastac, Laurentiu

“…Existing analytical models for calculating solute redistribution during the initial transient (unsteady) unidirectional solidification with an axially moving…”
Get full text