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Title: A Combined Experimental and Computational Approach for the Design of Mold Topography that Leads to Desired Ingot Surface and Microstructure in Aluminum Casting.

Journal Article · · Materials Science and Engineering: A

A thermomechanical study of the effects of mold topography on the solidification of Aluminum alloys at early times is provided. The various coupling mechanisms between the solid-shell and mold deformation and heat transfer at the mold/solid-shell interface during the early stages of Aluminum solidification on molds with uneven topographies are investigated. The air-gap nucleation time, the stress evolution and the solid-shell growth pattern are examined for different mold topographies to illustrate the potential control of Aluminum cast surface morphologies during the early stages of solidification using proper design of mold topographies. The unstable shell growth pattern in the early solidification stages results mainly from the unevenness of the heat flux between the solid-shell and the mold surface. This heat flux is determined by the size of the air-gaps formed between the solidifying shell and mold surface or from the value of the contact pressure. Simulation results show that a sinusoidal mold surface with a smaller wavelength leads to nucleation of air-gaps at earlier times. In addition, the unevenness in the solid-shell growth pattern decreases faster for a smaller wavelength. Such studies can be used to tune mold surfaces for the control of cast surface morphologies.

Research Organization:
Cornell Univ., Ithaca, NY (United States)
Sponsoring Organization:
USDOE Office of Industrial Technologies (OIT) - (EE-20)
DOE Contract Number:
FC36-02ID14396
OSTI ID:
850519
Report Number(s):
DOE/ID/14396; Report 6 of 7
Journal Information:
Materials Science and Engineering: A, Vol. 404, Issue 1-2; Conference: L. Tan and N. Zabaras, "Modeling the effects of mold topography on aluminum cast surfaces", presented in the symposium on `Solidification of Aluminum Alloys: Gas Porosity/Micro-Macro Segregation' (M. Chu and Q. Han, organizers), in the proceedings of EPD Congress 2004, TMS (The Minerals, Metals & Materials Society), 2004 TMS Annual Meeting & Exhibition, Charlotte, North Carolina, March 14-18, 2004
Country of Publication:
United States
Language:
English