不同鍛造製程對AA7075機械性質與抗腐蝕能力的影響

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Title:	不同鍛造製程對AA7075機械性質與抗腐蝕能力的影響
Authors:	許赫驖;Hsu, Ho-Tieh
Contributors:	機械工程學系
Keywords:	Al-Zn-Mg-Cu合金;鍛造;晶界角度;機械性質;抗腐蝕能力;Al-Zn-Mg-Cu Alloy;forging;angle grain boundary;mechanical properties;corrosion resistance
Date:	2021-07-08
Issue Date:	2021-12-07 13:16:55 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究探討不同鍛造製程對7075鋁合金(AA7075)機械性質與抗腐蝕能力的影響。實驗中對退火後AA7075的擠製棒材使用不同的鍛造條件(鍛造壓縮率及鍛造溫度)，之後進行固溶、焠火以及時效處理(T73)，再將試棒按照ASTM-E8規範進行CNC加工，隨後進行拉伸試驗量測，進而分析不同鍛造溫度及變形量的條件下，材料微結構對機械性質的影響。將拉伸試驗後的試棒縱剖後研磨、拋光並透過光學顯微鏡(OM)觀察試棒的微結構；後續利用影像分析軟體分析二次相顆粒的大小、數量及析出位置，探討二次相顆粒對於機械性質的影響。利用雙束聚焦離子顯微鏡(FIB)製備穿透式電子顯微鏡(TEM)試片，藉由能量色散X-射線光譜(EDX)分析析出物的成份，以及利用掃描式電子顯微鏡(SEM)的電子背向散射繞射分析儀(EBSD)，分析高低晶界角度比例。實驗結果分析顯示，AA7075在不同鍛造溫度及變形量的條件下皆符合規範要求(UTS?505 (Mpa)、YS?435 (MPa)、TEL?13%)。AA7075鍛件上高角度晶界長度增加會加速鍛件的腐蝕速率提高Icorr值。 ;The effects of different forging processes on mechanical properties and corrosion resistance of AA7075 were investigated in this study. The annealed AA7075 extruded bars which were produced by different forging processes (forging temperature and reduction rate) processed the solution treatment, water quenched and T73 artificial aging treatment. The samples were machined to the tensile bars according to ASTM-E8 specification, and then the tensile bars were tested to get tensile properties to analyze the effects of different forging temperatures and reduction rates on mechanical properties and microstructures. Finally, polished longitudinal sections of different samples were observed by the optic microscope (OM), scanning electron microscope (SEM), transmission micro-scope (TEM) to analyze of second phase particle particles, dispersoids and grain boundary angles. Experimental results demonstrate that all AA7075 samples after different forging processes compliance with specification (UTS?505 (Mpa)、YS?435 (MPa)、TEL?13%). Increasing the high misorientation angle grain boundary lengths (MAGBs) per unite area accelerated corrosion to lift up Icorr values.
Appears in Collections:	[Graduate Institute of Mechanical Engineering] Electronic Thesis & Dissertation

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