鋁合金2219與5083之銲接熱裂研究

THE STUDY HOT CRACK SUSCEPTIBILITY OF ALUMINUM ALLOYS 2219 AND 5083

洪耀宏

指導教授 ： 屠名正 ； 周長彬

國立臺灣師範大學/科技學院/工業教育學系/碩士(2002年)

摘要

本研究選用2219-T31與5083-O鋁合金為母材，利用可調應變試驗機（Varestraint Test）在銲接時施以不同的變形量與不同的熱循環次數，比較兩種鋁合金的熱裂敏感性。此外，對於熱處理型鋁合金，在銲前施以銲前熱處理，以討論熱處理對材料熱裂敏感性之影響。銲後並進行微觀金相組織觀察，加以探討熱裂縫的發生型態。
研究結果顯示，隨著變形量的增加，熱裂敏感性也隨之增加；隨著熱循環次數的增加，熱裂敏感性亦隨之增加。鋁合金5083-O的銲接熱裂性質較2219-T31佳。對於熱處理型鋁合金2219-T31，銲前熱處理會使材料的熱裂敏感性增加。而金相組織的排列與大小則會影響裂縫延伸的難易度。銲件破斷面經由SEM觀察，可以發現凝固型組織和液化型組織，可以驗證破壞原因係屬熱裂沿晶破壞。

關鍵字

鋁合金 ； 銲接熱裂

並列摘要

The purpose of this research is to study and prove the heat crack susceptibility of Aluminum Alloys 2219-T31 and 5083-O. The effect of augment strain and the thermal cycle of heat input to test the crack sensitivity for GTAW welding metal of aluminum alloy by using the Varestraint Test. In addition, for heat-treatment alloy is to prove, discuss the effect of heat crack sensitivity for pre-weld heat treatment. Optical microscope metallography was used to determine and analyze the effects, after welding.
A series of experiment result is indicated that, the augmented strain can be increased the crack sensitivity. The increase of the thermal cycle in heat input will gradually increase the crack sensitivity. Alloy 5083-O is safer and better compare to 2219-T31 as the crack sensitivity is lower. The alloy 2219-T31 is better to use for pre-weld heat treatment, as the crack sensitivity is low. The crack sensitivity can be affected by the different arrangement and the sizes of the microscope grain.
The result from SEM observations on the welded-broken specimen proved that the solidification cracking and liquefaction cracking, for heat cracks were observed to initiate and propagate along grain boundaries in both the fusion zone and weld heat-affected zone.

參考文獻

3、盧仲湘（1989）。高強度鋁合金之銲接熱裂研究。國立交通大學機械工程研究所。

19、中華民國焊接學會編印（1997）。銲接工程管理基礎課程。台北：中華民國銲接學會。

2、林忠傑（2000）。冷加工及銲後熱處理對1050鋁合金銲件機械性質影響之研究。國立台灣師範大學工業教育研究所碩士論文。

5、周文斌（2001）。銲前冷加工對AISI 316 不?袗?機械性質之研究。國立台灣師範大學工業教育研究所碩士論文。

12、Hsiao I. C. & Huang J. G.(1999).Development of low temperature superplasticity in commercial 5083 Al-Mg alloys. Scripta Materialia, vol.40, 697-703.