臺灣博碩士論文加值系統

本研究使用傳統立式銑床改裝之摩擦攪拌銲接機及可量測軸向負荷之工作平台，使用高速鋼、Nimonic 75超耐熱合金及Inconel 600超耐熱合金三種工具材料，在工具傾角1.5°、工具轉速1000 rpm以及不同進給速度45 mm/min、60 mm/min、86 mm/min之條件下，對厚度20 mm 純銅板進行摩擦攪拌銲接。在固定實驗條件情況下，討論不同工具材料與探針幾何對探針變形的影響。最後探討進給速度對銲接軸向負荷、溫度變化及接合強度之影響，並透過金相觀察討論進給速度對銲道機械性質的影響。
研究結果顯示，摩擦攪拌單點銲接中，使用三種工具材料進行實驗，持壓時間均為10秒即能達到飽和溫度870°C，並在實驗後觀察工具，發現高速鋼工具在銲接後有明顯變形，不適合作為工具材料，故將超耐熱合金作為主要工具材料，並進行多次實驗，以確保工具的重複使用性。此外，在固定實驗條件下，探針幾何對銲道及工具變形的影響，錐度40°之探針幾何由於探針尖端材料較少，銲接時容易造成工具變形，並且對試片底部的材料帶動不完全，導致材料回填不足，容易形成空孔缺陷，故將錐度30°之探針幾何作為主要工具參數。
最後探討進給速度對銲道的影響，在進給速度45~86 mm/min之條件下，銲道的拉伸強度無明顯的變化。試片的上半部有較強的拉伸強度，能達到母材拉伸強度的90%以上，伸長率則能達到母材伸長率的75%以上；試片的下半部則因為試片底部的攪拌會較不均勻，拉伸強度較低，但也能達到母材拉伸強度的80%以上，伸長率則為母材伸長率的40%以上。此外，進給速度越快則會使工件硬度些微上升，並且透過金相觀察可得知，進給速度越快，攪拌區內的晶粒會更細化。

In this study, 20 mm thick pure copper plates were friction stir welded (FSW) by three different tool materials at tilt angle of 1.5°, tool rotating speed of 1000 rpm, and different feed speeds to investigate the effect of tool material and pin geometry on the pin deformation. In the FSW experiments, the downward force and the temperature were measured to record their time histories. Finally, effects of feed speed on the downward force, the temperature and the joint strength were investigated. The mechanical properties of the weld were discussed by observing the metallography of the fractured surface in the tensile test after welding.
Experimental results show that the temperature achieved 870°C after dwell time of 10 seconds in the friction stir spot welding using three tool materials. The high-speed steel tool was obviously deformed after welding, and it was not suitable as a tool material. Inconel 600 and Nimonic 75 were selected as the materials with the tool reusability. The pin with the angle of 40° was easy to deform during FSW process due to less material at its tip. Moreover, the material at the bottom of the workpiece was not fully driven, resulting in insufficient backfilling of the material with void defects. Consequently, the pin with the angle of 30° was selected.
Results showed that the tensile strength of the weld had no obvious variation under the feed speeds of 45~86 mm/min after FSW process. The top of workpieces could achieve more than 90% of tensile strength of pure copper, and the elongation could achieve more than 75% of base metal. Since stirring was less uneven at the bottom of workpieces, it had more than 80% of tensile strength, and the elongation could achieve more than 40% of base metal. In addition, the faster the feed speed, the slighter the hardness of the workpiece, due to the finer the grain in the stirring zone by observing the metallography of the weld.

論文審定書 i
致謝 ii
摘要 iv
Abstract v
目錄 vi
圖次 viii
表次 xiii
第一章 緒論 1
1.1 研究背景 1
1.2 文獻回顧 3
1.2.1 工具轉速對銲道的影響 3
1.2.2 進給速度對銲道的影響 5
1.2.3 下壓力對銲道的影響 8
1.2.4 工具傾角對缺陷的影響 9
1.2.5 工具幾何對銲接的影響 10
1.2.6 純銅摩擦攪拌銲接之特性 23
1.3 研究目的 31
第二章 實驗設備與實驗方法 33
2.1 實驗設備 33
2.1.1 工作台 34
2.1.2 溫度量測背板 36
2.1.3 摩擦攪拌銲接工具與試片 37
2.2 實驗方法 40
2.3 極限拉伸試驗 42
2.4 金相觀察與微硬度試驗 44
2.5 實驗流程 45
第三章 實驗結果 46
3.1 單點銲接 46
3.1.1 工具材料探討 46
3.1.2 工具尺寸探討 49
3.1.3 工具重複使用性探討 52
3.2 進給銲接 55
3.2.1 工具材料對進給銲接之探討 55
3.2.2 工具錐度對銲道的影響 59
3.3 進給速率對軸向負荷與溫度之影響 63
3.4 進給速率對銲道強度之影響 69
3.5 銲道剖面之金相觀察 72
3.6 微硬度分布 74
第四章 結論與未來展望 75
4.1 結論 75
4.2 未來展望 77
參考文獻 78

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