Effect of Temperature and Fluid Flow on Dendrite Growth During Solidification of Al-3 Wt Pct Cu Alloy by the Two-Dimensi
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e most commonly observed during the solidification process, is closely associated with the final properties of welding and casting products.[1–4] The dendrite growth is a complex physical process significantly influenced by heat and solute transfer as well as fluid flow during solidification. To improve mechanical performance of the final products, it is valuable to study the key factors affecting the evolution of dendrites. Experimental tests are great useful methods for the examination of solidification microstructure. Salloum-Abou-Jaoude et al.[5] carried out the in situ and real time observations of the equiaxed grain motion during directional solidification of Al-10 wt pct Cu under CHENG GU, YANHONG WEI, RENPEI LIU, and FENGYI YU are with the College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China. Contact email: [email protected] Manuscript submitted May 22, 2017.
static magnetic field by means of synchrotron X-ray radiography. Shevchenko et al.[6] investigated the directional bottom–up solidification of Ga-25 wt pct In alloys by using the X-ray radioscopic technique and chose three experiments for examining the effect of natural and forced convection on the growth behavior of the Indium dendrites. Murphy et al.[7] presented experimental results of near-isothermal equiaxed solidification on the Al-Cu system performed in situ with laboratory-based radiography. All of the preceding research shows that the advances achieved in compact microfocus X-ray source and detector technology have made solidification experiments possible. However, these works mainly focused on directional solidification, and the experiments were performed with many conditions limited, which made it hard to obtain the dynamic evolution of microstructures under the condition of elevated temperature, especially under that of welding solidification, where the various temperature fields and flow fields appear. With the improvement of computer technology and the advancement of material science in recent years, numerical simulation of microstructure evolution during solidification has led to great achievements.[8–12] Dong and Lee[9] applied a combined cellular automaton-finite
difference (CA-FD) model to simulate the columnar-to-equiaxed transition during the directional solidification of Al-Cu alloys. Pan and Zhu[13] developed a three-dimensional (3-D) sharp interface model to simulate the solutal dendritic growth in the low Pe´clet number regime. Zheng et al.[14] developed a phase field (PF) model to investigate the microstructure evolution near the fusion line during solidification of the gas tungsten arc welding pool for aluminum alloy 2A14. Takaki et al.[15] investigated the primary arm array during directional solidification of a single-crystal binary alloy by large-scale PF simulations using the GPU supercomputer TSUBAME 2.5. Krane et al.[16] developed a cellular automaton-finite volume model (CA-FVM) to simulate dendrite growth in binary alloys. This research is important and useful for understanding
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