摘要 本研究主要是探討在加熱過程中，不同元素對於鎂合金發生燃燒反應的溫度的影響。使用的實驗材料為商用鎂鋁合金（純鎂、AZ61A、AZ80A和AZ91D）以及自行熔煉的鎂鈣與鎂鋁錳合金。另外，利用自行設計的加熱測溫裝置，比較鋁、鈣、錳等三種元素，對於抑制鎂合金燃燒的效果。 實驗結果發現鎂鋁合金發生燃燒反應的溫度，會隨著合金中鋁含量的增加而降低，主要是因為合金基地中的鎂鋁低熔點共晶物的含量會隨著鋁的添加量增加而增加，使合金容易發生局部熔解的情形，進而破壞合金表面原本的保護層，導致燃燒。 而添加鈣到鎂合金中，則是添加量愈多，發生燃燒反應的溫度愈高，主要原因是鈣會形成一層緻密的氧化層，阻止合金中的鎂元素與空氣中的氧做進一步的接觸。 鎂鋁錳合金中，錳含量增加也會提高合金發生燃燒反應的溫度，因為錳含量提高會消耗合金基地中更多的鋁元素，以形成Al6Mn析出物，所以合金中的低熔點鎂鋁共晶物的量會因此而減少，導致合金發生燃燒反應的溫度有提高的現象。 Abstract The purpose of this study is aimed at investigating the difference of the ignition temperatures affected by adding elements, Al、Ca、Mn, into magnesium alloys. The alloys used in this experiment are commercial Mg-Al alloys ( pure magnesium, AZ61A, AZ80A, AZ91D ) and Mg-Ca、Mg-Al-Mn alloys melted by designed apparatus. Experimental results show that adding more aluminum into magnesium alloys would lower the ignition temperature of the alloys. Inversely, adding more calcium and manganese into magnesium alloys would raise the ignition temperatures. Aluminum added into magnesium alloys would form low melting point eutectics, leading to local melt and therefore lowering the ignition temperature. Eventually, the specimens would burn out during experiment. However, adding calcium into magnesium alloys would retard the ignition process by forming thin and dense CaO films on the surface of the alloys. In the Mg-Al-Mn alloys, increasing manganese content increase the ignition temperature due to a great percent of precipitate, Al6Mn, formed leading to decrease amount of low melting point eutectics. So adding manganese would increase the ignition temperature of the magnesium alloys.
