The effect of the melt thermal gradient on the size of the constitutionally supercooled zone

4th International Conference on Advances in Solidification Processes

材料科学;物理学

Prasad, A.^1 ; Yuan, L.^2 ; Lee, P.D.^2 ; Easton, M.^3 ; StJohn, D.^1

Centre for Advanced Materials Processing and Manufacturing, University of Queensland, Brisbane, Australia^1

The Manchester X-ray Imaging Facility, School of Materials, University of Manchester, Oxford Rd., Manchester

M13 9PL, United Kingdom^2

School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne, Australia^3

关键词: As-cast;    Constitutional supercooling;    G-values;    Grain size;    Solidification modeling;    Test case;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/117/1/012001/pdf
DOI  :  10.1088/1757-899X/117/1/012001

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Recent verification of the analytical Interdependence model by a numerical solidification model (μMatIC) confirmed the critical role of constitutional supercooling (CS) in achieving sufficient undercooling to trigger successful nucleation events. The location of the maximum amount of CS (ΔTCSmax) is some distance from the interface of the previously growing grain and this distance contributes to the final as-cast grain size. The effect of the thermal gradient, G, on the size of the CS zone (CSZ) was neglected in that work. However, G is expected to affect the size of the CSZ (i.e. the length of the CSZ, x'CSZ, and the location of ΔTCSmax, x'CSmax). This investigation assesses the effect of G on x'csz and x'CSmax. A range of G values is introduced into both the analytical and the numerical models to obtain a correlation between the value of G and the dimensions of the CSZ. The result of a test case from the analytical model shows that x'CSmaxinitially decreases rapidly and then decreases gradually approaching zero at very high values of G. Independent of the analytical model, the results from the numerical model replicate the trend obtained from the analytical model.