Solidification with a Thermal Gradient in L-PBF (Equiaxed+Columnar) (1D_Temp)

dendritic solidification, eutectics, peritectics,....
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venkatesh.pandi97
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Solidification with a Thermal Gradient in L-PBF (Equiaxed+Columnar) (1D_Temp)

Post by venkatesh.pandi97 » Sun Sep 26, 2021 7:44 pm

Dear Bernd,

I am trying to simulate both equiaxed and columnar grain structures in my simulation for ferritic steel with the ODS system included during the AM solidification process. As a part of my first approach, I tried to simulate the equiaxed structure with the seed-density model and turned out to be successful. At present, I am trying to use the 1D_temp model as a reference to start with and I am initially trying to follow the approach described by Oba et.al (1) to map both the equiaxed and columnar structure. Unfortunately, I am facing the following problems

1. I have two different cooling rates (ie. top and bottom of the melt pool) to be inputted, but apart from the initial top and bottom temperature, I don't find a way to include both these data into my input file.

2. When I try to define two initial temperatures for the bottom and top, for example, 1000°C at the bottom and 2000°C at the top, I don't see any strong temperature gradients in the temp.mcr output either at the top or bottom rather only a difference of 10-20°C.

Thanks

Best Regards
Venkatesh

References
1. https://www.researchgate.net/publicatio ... eld_Method

Bernd
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Re: Solidification with a Thermal Gradient in L-PBF (Equiaxed+Columnar) (1D_Temp)

Post by Bernd » Sun Sep 26, 2021 10:40 pm

Dear Venkatesh,

Welcome to the MICRESS Forum.

I think there is some confusion about how the temperature boundary condition is applied. You say you want to use the "1d_temp" option of MICRESS, as it is shown e.g. in the A002_AlCu_Temp1d_dri example. With this approach, temperature is solved inside MICRESS using a macroscopic 1d-approximation, and in case of SLM you would have to define a Laser heat source as boundary condition of the 1d-temperature field.

However, in Oba et. al. (1), temperature has been solved in an external FEM solver and applied to the MICRESS simulation as boundary condition (using "profiles_from_file"). This means that the temperature difference between the top and the bottom of the MICRESS domain is an input (and not calculated by MICRESS). Perhaps their formulation "MPFM solidification simulation coupled with the 1D temperature field" is a bit misleading...

Bernd

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