Cellular-to-Dendritic and Dendritic-to-Cellular Morphological Transitions in a Ternary Al-Mg-Si Alloy

Joint 5th International Conference on Advances in Solidification Processes;5th International Symposium on Cutting Edge of Computer Simulation of Solidification, Casting and Refining

土木建筑工程;计算机科学

Brito, C.^1 ; Nguyen-Thi, H.^2 ; Mangelinck-Noël, N.^2 ; Cheung, N.^3 ; Spinelli, J.E.^4 ; Garcia, A.^3

Campus of São João da Boa Vista, São Paulo State University, UNESP, São João da Boa Vista/SP

13876-750, Brazil^1

Aix-Marseille Université, CNRS, IM2NP UMR CNRS 7334, Campus Saint Jérôme, case 142, Marseille Cedex 20

13397, France^2

Department of Manufacturing and Materials Engineering, University of Campinas, UNICAMP, Campinas/SP

13083-970, Brazil^3

Department of Materials Engineering, Federal University of São Carlos - UFSCar, São Carlos/SP

13565-905, Brazil^4

关键词: Application properties;    Evolution of the microstructure;    High cooling rates;    Morphological transitions;    Multi-component alloy;    Primary dendritic spacings;    Solidification condition;    Transient conditions;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/529/1/012018/pdf
DOI  :  10.1088/1757-899X/529/1/012018

来源: IOP

【 摘 要 】

The study is focused on the influence of solidification thermal parameters upon the evolution of the microstructure (either cells or dendrites) of an Al-3wt%Mg-1wt%Si ternary alloy. It is well known that the application properties of metallic alloys will greatly depend on the final morphology of the microstructure. As a consequence, various studies have been carried out in order to determine the ranges of cooling rates associated with dendritic-cellular transitions in multicomponent alloys. In the present research work, directional solidification experiments were conducted using either a Bridgman (steady-state) device or another device that allows the solidification under transient conditions (unsteady-state). Thus, a broad range of cooling rates (), varying from 0.003K/s to 40K/s could be achieved. This led to the identification of a complete series of cellular/dendritic/cellular transitions. For low cooling rate experiments, low cooling rate cells to dendrites transition happens. Moreover, at a high cooling rate, a novel transition from dendrites to high cooling rate cells could be observed for the Al-3wt%Mg-1wt%Si alloy. Additionally, cell spacing λC and primary dendritic spacing λ1 are related to the cooling rate by power function growth laws characterized by the same exponent (-0.55) for both steady-state and unsteady-state solidification conditions.