Al-Mg-Si鋁合金為析出強化型鋁合金，具有耐腐蝕性以及良好的銲接性且價格低廉，主用應用於建築以及汽車上。6082鋁合金在熱處理後之Al-Mg-Si鋁合金中具有最好的強度，但6082鋁合金經過高溫塑性變形以及攪拌材經高溫熱處理後會有晶粒粗大化之現象，其原因尚未有明確結論以及此現象對機械性質之影響需要釐清。本研究選用6082擠型材作為研究用母材，對其施以摩擦攪拌製程導入不同轉速(450、1050、1650 rpm)之高溫塑性變形與後續T4-T6 (560℃ 0.5~ 2hr, 170℃ 6hr)熱處理，觀察其微觀組織變化以及對常溫拉伸性質的影響。
研究結果顯示，隨著T4熱處理時間的增加，攪拌區內的晶粒粗大化情形也會隨之增加，晶粒粗大化之情形會先從攪拌區之頂部與底部開始出現，且晶粒成長速度較快，而高轉速攪拌材之組織高溫穩定性優於低轉速攪拌材，晶粒較不易粗大化，但晶粒容易粗大化之低轉速攪拌材則是外觀用件較恰當的表面改質參數。
常溫拉伸性質的部分，摩擦攪拌材未經後熱處理之攪拌區細小且均勻的組織使拉伸過程中裂紋較不易串連，因而攪拌後有較佳的拉伸延性。6082鋁合金經摩擦攪拌及後T4-T6熱處理，不同轉速之攪拌材在相同時間後熱處理下，攪拌區之組織粗大化情形會有所不同，而組織差異對拉伸強度則是沒有太大的影響，在拉伸變形時強度主要還是受析出強化主導而與晶粒粗大化較無關，拉伸延性則是會受到粗大化組織及組織均勻性的影響。但整體拉伸性質與未經摩擦攪拌製程前的6082鋁合金T4-T6材相比皆有劣化之現象。

6xxx Al alloy, a series of precipitation hardened Al alloys, is widely used in extruded aluminum products. The material used in this study is AA6082 which is optimized to be the strongest alloy in 6xxx series. Nowadays, AA6082 is majorly applied in automotive industry and construction. Friction stir process (FSP) is practicable for AA6082 and improve the ductility of AA6082, but the strength of friction stir processed (FSPed) AA6082 will be descended. In this study, post T4-T6 treatment was expected to promote the strength of FSPed AA6082, but the grains of FSPed AA6082 coarsened in the stir zone after solution treatment. To investigate the effects of FSP and post T4-T6 treatment on microstructural characteristic and tensile properties of material in the stir zone (SZ). The results showed that different rotation speed of FSP got different coarsening situation after T4-T6 treatment and low rotation speed of FSP which was easy to obtain coarse grains. And one thing should be noticed that tensile stresses of specimens with different rotation speed were almost identical. The result showed that grain size did not affect the strength in AA6082 after T4-T6 treatment. Precipitation hardening plays the major role in determining the strength of AA6082. And coarse grain would make material ductility decrease. However, tensile properties of post T4-T6 treatment FSPed AA6082 are still lower than T4-T6 treatment AA6082.

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