Deformation of Aluminium Dendrite

Sample

Many industrial processes involve the deformation of the semi-solid. The aim of the present study is to understand and simulate the deformation behaviour of semi-solid during twin roll casting of aluminium alloys.

A laboratory cast Al-12 wt.% Cu alloy is used as the test sample. The selection of the alloy is based on the favourable difference of x-ray attenuation coefficients between Al and Cu. The sample is directionally solidified and quenched to freeze the columnar dendrite structure.

X-ray Microtomography (XMT)

The quenched sample from the Bridgman furnace, which was a cylinder of 6 mm diameter and 60 mm in length, was scanned in a commercial XMT unit (V|tome|X – nano-focus, Phoenix|x-ray Systems and Services GmbH, Germany). A spot size of approximately 2 µm was used with accelerating voltage of 80 kV and a current of 80 µA. Polychromatic tungsten K_α radiation was used and transmitted radiation was recorded on a two-dimensional semiconductor type direct digital detector. A voxel size of 7.2 µm was achieved.

Dendrite formation Courtesy: NASA

Segmentation in ScanIP

Smoothed mesh model

Model generation in ScanIP and ⁺ScanFE

3D volumetric data from XMT was loaded on ScanIP and a single Al dendrite was segmented out from the Al-Cu matrix. The selected dendrite was easily meshed using ⁺ScanFE in under 5 minutes.

FE Simulation in Abaqus

Deformation of dendrite (more detailed image)

The deformation behavior of the meshed dendrite was simulated using Abaqus by applying a compressive displacement of 25 µm at the top face and fixing the bottom face. For this preliminary study, the dendrites were assumed to have the properties of pure aluminum, i.e. a Young’s Modulus of 73 GPa and Poisson’s ratio of 0.33.

Customer Testimonial

"Thanks to ⁺ScanFE meshing took only 5 minutes. This was not possible before as meshing techniques were not very efficient when it came to complex geometries. This has definitely helped in saving a lot of time." - Devashish Fuloria

Publication

Fuloria, D., Lee, P.D., Bernard, D., 2007. Determining the fluid flow and deformation behaviour of both simulated and measured columnar-dendritic structures in Al-Cu alloys. In: Solidification Processing 2007, 22-25 July 2007 Sheffield. p. 685.