本研究使用不同幾何特徵之螺紋攪拌工具對鋁合金5052進行不同製程參數之FSSW製程與拉剪破壞試驗，同時測量FSSW製程中銲件承受的力量與材料的溫度，藉此了解不同製程參數間材料流動行為的差異，並比較銲件強度及破斷形貌，找出影響FSSW製程中材料流動行為之關鍵因素。
實驗結果顯示FSSW製程中攪拌工具承受軸向力可分為兩階段，在第一階段中，低轉速下量測的軸向力較高，高轉速下量測的軸向力較低。在第二階段中，各轉速所量測的軸向力皆呈遞減現象。
分析不同轉速間之差異時，在材料應變相同下，因材料承受工具提供之功率與其流動應力上的差異，使攪拌區在低轉速下不易形成且不明顯，反之，攪拌區在高轉速下容易形成且明顯；在材料溫度則有明顯變動(最大上升約36 %)，使熱影響區之材料晶粒粗化，並因螺紋位置不同改變材料塑性流動區域，而影響上下板材溫度分布，工具B(螺紋長度1.0 mm，分布於工具凸銷根部位置(即靠近肩部位置))之銲件溫度量測以上板材最高，工具M、T(螺紋長度皆0.9 mm，分別分布於工具凸銷中段與頂端)之下板材溫度有明顯提升；在材料流動行為則因材料溫度梯度(暫態拘束空間的邊界)與材料參與塑性流動之來源有所差異，進而影響攪拌區擴大趨勢與範圍；低轉速時攪拌區不易往縱向發展擴大，而往橫向發展，高轉速時則反之；在銲件拉剪強度則受工具加工硬化效果、上板薄化問題、熱影響區溫升效應造成晶粒粗化等因素影響，使低轉速之銲件擁有較佳強度，高轉速之銲件強度則較差。

In this thesis, the effects of different process parameters on material flow with different geometric tools during friction stir spot welding (FSSW) are discussed. The experimental were divided into two parts. In the first, the welding specimens were used to investigate the material flowing behaviors during FSSW, and the strength under tensile tests was compared, Tool speeds range from 450 rpm to 2700 rpm, a plunging rate of 1 mm/s, a plunging depth of 2.8 mm and holding time of 1s, 1.2s, 1.5s, 2s, 3s, 3.6, 4.5s, 6s, 9s, 18s. In the second part, tool force and the material temperature were measured during FSSW.
Experimental results show that forces was higher in low rotational speed than those in high rotational speed due to the resistance of material, and the temperature of the upper sheet was the highest when using tool B, while an obvious temperature rising of the lower sheet was observed when using tool M、T. Due to the effect of effective thickness on the upper sheet, hardening made by tools and grain coarsening caused by temperature rising, the strength of welds has a great improvement when using tool T under the process parameter with low tool rotational speed during FSSW.

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