scholarly journals Effects of Static Magnetic Field on the Microstructure of Selective Laser Melted Inconel 625 Superalloy: Numerical and Experiment Investigations

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1846
Author(s):  
Wanli Zhu ◽  
Sheng Yu ◽  
Chaoyue Chen ◽  
Ling Shi ◽  
Songzhe Xu ◽  
...  

A number of researchers have reported that a static magnetic field (SMF) will affect the process of selective laser melting (SLM), which is achieved mainly through affecting molten pool evolution and microstructure growth. However, its underlying mechanism has not been fully understood. In this work, we conducted a comprehensive investigation of the influence of SMF on the SLM Inconel 625 superalloy through experiments and multi-scale numerical simulation. The multi-scale numerical models of the SLM process include the molten pool and the dendrite in the mushy zone. For the molten pool simulation, the simulation results are in good agreement with the experimental results regarding the pool size. Under the influence of the Lorentz force, the dimension of the molten pool, the flow field, and the temperature field do not have an obvious change. For the dendrite simulation, the dendrite size obtained in the experiment is employed for setting up the dendrite geometry in the dendrite numerical simulation, and our findings show that the applied magnetic field mainly influences the dendrite growth owing to thermoelectric magnetic force (TEMF) on the solid–liquid interface rather than the Lorentz force inside the molten pool. Since the TEMF on the solid–liquid interface is affected by the interaction between the SMF and thermal gradient at different locations, we changed the SLM parameters and SMF to investigate the effect on the TEMF. The simulation shows that the thermoelectric current is highest at the solid–liquid interface, resulting in a maximum TEMF at the solid–liquid interface and, as a result, affecting the dendrite morphology and promoting the columnar to equiaxed transition (CET), which is also shown in the experiment results under 0.1 T. Furthermore, it is known that the thermoelectric magnetic convection (TEMC) around the dendrite can homogenize the laves phase distribution. This agrees well with the experimental results, which show reduced Nb precipitation from 8.65% to 4.34% under the SMF of 0.1 T. The present work can provide potential guidance for microstructure control in the SLM process using an external SMF.

2007 ◽  
Vol 546-549 ◽  
pp. 2301-2306 ◽  
Author(s):  
Hua Tan ◽  
Jing Chen ◽  
Xin Lin ◽  
Xiao Ming Zhao ◽  
Wei Dong Huang

Laser rapid forming (LRF) is a new manufacturing technology, which has been developed on the basis of multi-layer laser cladding. In the LRF process, the microstructure has important effects on the mechanical properties of the partsbut the control of microstructure is a problem. In this study, the influences of crystallography orientations of substrate and profile of solid/liquid interface on microstructure were discussed. Further, with the combining of the columnar to equiaxed transition (CET) model during alloy solidification, the growth law of microstructure of Rene88DT alloy was established. It has been found that the temperature gradient was lowest and the solidification velocity was greatest at the solid/liquid interface of the tail of molten pool, and hence the CET occurs easily at this position. The temperature measurement system of molten pool was developed by using a two-color infrared thermometer in this study. With the measurement of temperature gradient of the tail of molten pool by using a two-color infrared thermometer, the process parameters of laser multi-layer cladding were optimized. Finally, directional solidification even single crystal was achieved in laser multi-layer cladding.


1993 ◽  
Vol 129 (1-2) ◽  
pp. 30-36
Author(s):  
K. Oda ◽  
T. Saito ◽  
J. Nishihama ◽  
T. Ishihara ◽  
M. Sato

2005 ◽  
Vol 04 (05n06) ◽  
pp. 995-999
Author(s):  
ABHISHEK CHAUDHURI ◽  
DEBASISH CHAUDHURI ◽  
SURAJIT SENGUPTA

We show how interfaces may be induced in materials using external fields. The structure and the dynamics of these interfaces may then be manipulated externally to achieve desired properties. We discuss three types of such interfaces: an Ising interface in a nonuniform magnetic field, a solid–liquid interface and an interface between a solid and a smectic like phase. In all of these cases we explicitly show how small size, leading to atomic-scale discreteness and stiff constraints produce interesting effects which may have applications in the fabrication of nanostructured materials.


2012 ◽  
Vol 217-219 ◽  
pp. 2006-2011
Author(s):  
Hong Jin Zhao ◽  
Gui Huan An ◽  
Wen Feng Zeng ◽  
Xin Luo

The effect of the position and shape of solid-liquid interface on process parameters has been studied by the numerical simulation method, and the reasonable process parameters have been given. The results shows that the position and shape of solid-liquid interface is mainly affected by mold temperature, casting speed and cooling distance. It were moved to the mold export with the improvement of the mold temperature, casting speed or the reduce of cooling capacity. And the reasonable process parameters are that the mold temperature is 1363-1373 K, casting speed is 80-100mm/min, cooling distance is 40-50mm. The research results would obtain stable operation conditions and improve the billet quality.


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