鋁鋰合金摩擦攪拌銲接性質之可靠度研究
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Date
2003-10-31
Authors
程金保
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Abstract
鋁鋰合金具有低密度、高比強度和比剛度、優良的低溫性能、良好的耐腐性能和非常好的超塑性等特性，是一種理想的航空與航太結構材料。 AA2091 鋁鋰合金為中強度鋁合金，比 2024-T3 低 8％之密度，高 7％之彈性係數，被發展來取代 2000 系列鋁合金。摩擦攪拌銲接技術是一種低變形、高品質、低成本的鋁合金接合方法，應用摩擦攪拌銲接應是提昇 Al-Li 合金銲接品質的有效方法，而其接合之可靠度則必須加以評估。本研究主要針對 AA2091-T3 鋁鋰合金板材經由不同的製程條件 (工具轉速、進給率 )實施摩擦攪拌銲接，進行對接接合，探討其銲接區域之顯微結構組織與機械性質之變化，以尋求適當之接合條件。研究結果發現工具轉速在 550~2500 rpm、進給率 87~187 mm/min 之範圍皆能得到良好之接合表面，顯微組織觀察並未發現縮孔或裂痕，銲道與母材之微硬度值並無明顯差異，拉伸試驗破斷的位置都遠離銲塊。
The need to reduce weight and improve fuel economy in aerospace applications has led to increase use of lightweight materials such as aluminum-lithium alloys. The Al-Li alloys have low density, high specific modulus, and excellent toughness properties. However, the welding properties and reliability must be understood and explored further. Friction stir welding (FSW) is an emerging solid-state joining process that produces low-distortion, high-quality, low-cost welds. The joining properties of Al-Li alloy may be ameliorated by the friction stir welding technology. The objectives of this work are to explore the joining properties of friction stir welding for AA2091 (Al-Cu-Li-Mg) alloys by different welding conditions. To produce a high integrity Al-Li alloy weld, process variables (550~2500RPM and material of the shoulder-pin assembly, traverse speed) and the tool pin design of friction stir welding has been chosen carefully. The best joining and mechanical properties of friction stir welding of Al-Li alloy were elucidated about the effect of process variables.
The need to reduce weight and improve fuel economy in aerospace applications has led to increase use of lightweight materials such as aluminum-lithium alloys. The Al-Li alloys have low density, high specific modulus, and excellent toughness properties. However, the welding properties and reliability must be understood and explored further. Friction stir welding (FSW) is an emerging solid-state joining process that produces low-distortion, high-quality, low-cost welds. The joining properties of Al-Li alloy may be ameliorated by the friction stir welding technology. The objectives of this work are to explore the joining properties of friction stir welding for AA2091 (Al-Cu-Li-Mg) alloys by different welding conditions. To produce a high integrity Al-Li alloy weld, process variables (550~2500RPM and material of the shoulder-pin assembly, traverse speed) and the tool pin design of friction stir welding has been chosen carefully. The best joining and mechanical properties of friction stir welding of Al-Li alloy were elucidated about the effect of process variables.