凝固過程是金屬材料鑄造中的重要階段，決定材料性能優劣的微觀組織在此階段形成，其中本文所關心的是澆注時金屬液流動速度對於枝狀晶成長型態的影響。
本文採用修正後自動細胞機方法(Modified cellular automaton method, MCA method)模擬流場效應對鋁銅合金凝固過程中枝狀之晶微組織的影響。本文以巨觀熱傳為基礎，結合微觀的成核、成長模式，並且在微觀濃度之計算中加入金屬液之流動，在液固相的變化過程中，預測枝狀晶在流場效應下之成長型態。在成長模式中，本文根據 KGT (Kurz-Giovanola-Trivedi)模型計算枝狀晶頂端之速度。
本文以上述之模式模擬自由枝狀晶在流場效應下的凝固過程，觀察流場效應對枝狀晶頂端成長速度、溶質分布所造成的影響，並討論枝狀晶不同位置受到流場影響所產生之差異性。另外，本文選擇不同的優先成長角度和不同的流速去觀察不同枝狀晶成長型態間的異同，並利用枝狀晶頂端成長速度隨著時間的變化去分析金屬液流動對成長型態的影響。因枝狀晶成長對流場的改變本文亦作深入的探討。

Solidification is a crucial process in casting metal material. The microstructure is formed at this stage. Indeed, this research aims at the flow impact for the growth patterns of a dendrite during the solidification process.
This research has adopted the Modified cellular automaton (MCA) model to simulate the effects on dendritic microstructures during the Al-Cu alloy solidification. Based on the macro-model of heat transfer, microscopic nucleation, growth kinetics, and the liquid flow in the solute calculation are considered to predict the growth patterns of a dendrite. This research calculates the velocity of a dentritic tip using the KGT model.
In the proposed study, the tip growth velocity and solute distribution are observed to analyze the flow impact, and the differences between the observed locations of the dendrite are further discussed. In addition, the research has predetermined various growth angles and uniform velocities to study the similarities and dissimilarities between dentritic morphologies. Moreover, the study uses the profile of tip growth velocity vs. calculation time to evaluate the convection effect on the growth patterns. It has also brought a deeper discussion regarding to the flow variations influenced by the dentritic growth.

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