電子束的主要優點是能夠理想的溶銲異種金屬，對不同熱性質的金屬有很好的接合能力，但美中不足的是它會產生錯（Missed- Joint）.因為能量聚焦於直徑0.1mm∼1mm的能量半徑內做一個深且窄的銲接，造成工件極高溫差，非平衡熱力西貝克效應(Seebeck Effect)產生，因而產生熱電流引發熱電磁場，電磁力造成電子束在整個銲接過程中偏折，造成接合處形成非對稱的熔融區,甚至熔融區完全錯接。
本研究從選擇不同材料組合，量測錯接數據，作分析比較，探討電子束銲接機工作參數如加速電壓，銲接電流，銲接速度，Focus位置，真空度以及材料特性如導磁率，熔點，熱傳導，熱擴散，導電率，和絕對熱起電力(Absolute thermoelectric power)對錯接之影響。找出影響偏折的參數，及預防偏折方法，以提高銲接準度，提升銲接品質。
結果須配合材料物理性質，選擇絕對熱起電力，導磁率相近的材料組合;調整機器參數在執行電子束銲接時給予最佳銲接功率,適當入射角，或者提高銲接速度,減小焦距(Focus distance),減少熱輸入量(Heat-Input)等都可以有效抑制偏折發生。

A three-Dimensional deflection of the electron-beam resulting a missed joint
due to thermoelectric magnetism generated in welding dissimilar metal is experi-
mentally and analytically investigated.
In theoretical analyisis a narrow welding cavity is assumed to be a paraboloid of revolution. Applying a three-dimensional analytical solution of thermolectric currents, magnetic fiux densities, and deflections of the electron beam are determined from Maxwell's electromagnetic equations. The computed magnetic fields,thermoelectric currents and beam deflection will be compared to experimental results. Factors affect-ing deflection are discussed.
The major advantage of welding with a high-power-density-electron-beam is
the ability to weld dissimilar metals, unfortunately, can be missed. when the beam from the electron gun is properly aligned with the joint, subsequent deflection of the beam can result in nonsymmetric fusion along a joint, or the fusion zone may miss the joint .One reason responsible for the beam deflection is due to thermoelectric magnetic fields.
Since temperature gradients exist between the top and bottom and in front and be-hind the deep and narrow cavity ,thermoelectric currents due to the Seebeck effect are produced in dissimilar metals. The induced magnetic field above and below the top surface therefore deflects the electron-beam and induces a missed joint in S-shaped.
In this study, experiments will be conducted to measure missed joints. A three-dimensional thermoelectric and heat conduction model is also to predict deflection of an electron-beam From the surroundings and to bulk workpieces, the entire trajectory of the beam can be determined.a more systematical and realistic understanding on missed joint parameters.

第一章、 前言 ------------------------------------ 1
第二章、實驗設備 ----------------------------- 11
第一節、電子束銲接機 -------------------- 11
第二節、試片加溫器 ----------------------- 15
第三節、高斯計 ------------------------------ 16
第三章、實驗方法與步驟 -------------------- 20
第一節、電子束銲接 ----------------------- 20
第二節、量測熱起電力 ---------------------- 25
第四章、實驗結果 -------------------------------- 31
第五章、理論分析 -------------------------------- 40
第一節、Scale analysis ------------------------- 40
第二節、無因次分析 ------------------------- 47
第六章、結果與討論 ----------------------------- 51
第七章、結論 --------------------------------------- 62
第八章、參考文獻 -------------------------------- 63
第九章、附錄 --------------------------------------- 66

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