微量Zr對AA1050鋁合金機械性質之影響

On the study of high strength and high toughness of AA1050 Al-alloy containing minor Zr

邱揚淳(Yang-Chun Chiu)

指導教授 ： 李勝隆 ； 李天錫

國立中央大學/工學院/機械工程學系/碩士(2014年)

摘要

AA1050為商用純鋁，具有良好的加工性、延展性等優點，然而AA1050在鋁合金中屬於強度最低者之一，使其應用大幅被限制，可以藉由嚴重塑性變形將AA1050加工成晶粒尺寸為1μm之極細晶(ultrafine-grained)材料，其硬度與拉伸強度較未加工之AA1050上升一倍以上，但延性與應變硬化應變能大幅下降。
本研究藉由添加微量Zr與均質化處理後以不同速率冷卻而改變AA1050合金內元素固溶量，探討固溶量對其機械性質之影響;結果顯示經均質化爐冷處理後的合金，由於Al3Zr第二相的析出，於鋁基地中阻礙差排移動之固溶元素極低，導致合金強度與應變硬化能力均不佳。而經均質化水淬處理後的合金為一過飽和固溶體，鋁基地較爐冷合金擁有更多固溶元素以阻礙差排移動，導致合金之強度與應變硬化能力的提升。且對於含低固溶量原子之AA1050鋁合金，固溶量的增加，對合金之延性與應變硬化應變能無明顯影響; 而含較高固溶量原子之AA1050鋁合金，固溶量的增加，對合金之延性與應變硬化應變能顯現較明顯之提升效果。而在含鋯極細晶AA1050合金中，Zr固溶量增加對其延性與應變硬化應變能之提升相較於對其硬度與強度來得更加顯著。

關鍵字

鋁合金 ； 極細晶 ； 應變硬化 ； 應變硬化應變能 ； 機械性質

並列摘要

AA1050 is a commercial pure aluminum, having good workability and good ductility. Because it’s one of the lowest strength aluminum alloys, its application has been limited. AA1050 can be processed into 1μm fine grain (ultrafine-grained) material by severe plastic deformation, then AA1050’s hardness and tensile strength can increase up to 100%, but the ductility and strain hardening strain energy drop significantly.

By the microstructure and tensile test, the investigate shows the effect of cooling rates after homogenization to mechanical properties of AA1050 with minor Zr; The effect of furnace cooling results that AA1050’s strength and strain hardening capacity are poor due to low solutes dragging dislocations moving. The effect of water quenching results that AA1050 enhances the strength and strain hardening capacity because the alloy became supersaturated solid solution and have more solutes than furnace cooling to drag dislocations moving. To the atoms with lower solution amount in AA1050, increasing the amount of solutes can’t enhance AA1050’s ductility and the strain energy of strain hardening; To the atoms with higher solution amount in AA1050, increasing the amount of solutes has the obvious effect to enhance AA1050’s ductility and the strain energy of strain hardening.
In ultrafine-grained AA1050 containing Zr, increasing Zr solid solution enhances AA1050’s ductility and strain hardening strain energy more significantly than its hardness and strength.

並列關鍵字

aluminum ； ultrafine-grained material ； strain hardening ； strain hardening strain energy ； mechanical properties

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