摩擦攪拌銲接製程參數對5083-O鋁合金接合性質之影響

Abstract

摘 要

摩擦攪拌銲接是一種低變形、高品質之固態接合技術，能有效提昇鋁合金之銲接品質。本研究主要經由微觀組織分析及機械性質測試，探討摩擦攪拌銲接製程參數對5083-O鋁合金銲後接合性質之影響。製程參數包含傾斜角度、凸肩下壓深度、轉數及銲接速度，接合方式係採取對接接合。 研究結果發現使用18-4-1高速鋼材質之攪拌桿，並將攪拌桿沿進給軸方向傾斜1度，搭適當的工具轉速為550~1100 rpm、進給87~267 mm/min，能得到良好之接合效果。顯微組織觀察並未發現縮孔或裂痕，在攪拌區可觀察到細化之動態再結晶現象；微硬度測試結果則顯示在適當的銲接條件下，試片攪拌區的微硬度值最高，但與母材之硬度值並無明顯差異。而試片接合區域之熱機影響區寬度，隨著銲接速度的增加而縮減。 此外，研究結果亦顯示，在傾斜角1度及凸肩下壓深度0.15 mm之設定條件下，取摩擦攪拌銲接參數(ΘFSW) 值為4.1，即銲接速度267 mm/min搭配轉數1100 rpm進行銲接，可得到較佳之接合品質。綜合拉伸試驗結果及ΘFSW 值之分析，符合銲接品質要求之摩擦攪拌銲接參數之ΘFSW 值範圍在3.2至9.2間。

Abstract

Friction stir welding (FSW) is an emerging solid-state joining process that produces low-distortion, high-quality, low-cost welds. The welding properties of aluminum alloys may be ameliorated by the friction stir welding technology. The objective of this study is to demonstrate the feasibility of FSW for joining of 5083-O aluminum alloy by different welding conditions. To produce high integrity welds, the process variables (RPM and material of the shoulder-pin assembly, traverse speed), the tilt angle and the tool pin design of friction stir welding must be chosen carefully. Microstructures of the welds will be examined using optical microscopy (OM). The best joining and mechanical properties of friction stir welding of Al alloy were elucidated about the effect of process variables. According to the experimental results of microstructure examination and microhardness test, the fine recrystallized grains in the stir zone and the elongated grains in the thermo-mechanical affected zone were created during friction stir welding. The hardness in the stir zone is the highest, the thermomechanically affected zone (TMAZ) and the base metal is lower. In proper welding conditions, the width of TMAZ zone decreases with increasing of the welding speed. Furthermore, the better joining quality can be achieved by the proper manufacture parameters. According to the analysis of tensile tests, the proper range of FSW parameters (ΘFSW) are from 3.1 to 9.2.