DC 欄位 |
值 |
語言 |
DC.contributor | 機械工程學系 | zh_TW |
DC.creator | 劉國政 | zh_TW |
DC.creator | Guo-Jheng Liou | en_US |
dc.date.accessioned | 2008-7-2T07:39:07Z | |
dc.date.available | 2008-7-2T07:39:07Z | |
dc.date.issued | 2008 | |
dc.identifier.uri | http://ir.lib.ncu.edu.tw:444/thesis/view_etd.asp?URN=953203027 | |
dc.contributor.department | 機械工程學系 | zh_TW |
DC.description | 國立中央大學 | zh_TW |
DC.description | National Central University | en_US |
dc.description.abstract | 本論文以LAZ1110鎂合金為基本,添加微量Be、Sc元素,形成LAZ1110、LAZ1110+Sc、LAZ1110+Be及LAZ1110+Be,Sc四種合金,除了觀察添加微量Be、Sc元素對LAZ1110在微結構及機械性質的影響外,亦藉由等通道彎角擠製(ECAE)嘗試細化晶粒及探討擠製後之常溫機械性質、微結構的變化,並對ECAE後材料進行退火處理,觀察微結構及硬度值的變化。
比較四種原材之微結構,LAZ1110合金添加Sc,有晶粒細化的效果。LAZ1110合金添加Be,會產生兩種微結構的影響,晶粒粗大及費德曼組織。在機械性質部分,抗拉強度以LAZ1110+Be最高,達151 MPa,較LAZ1110+Sc的147 MPa高,在此以添加Be產生費德曼組織的析出強化效果較添加Sc的細晶強化好。
四種原材於室溫經ECAE後,LAZ1110合金經120°-RT-C4擠製後,晶粒從25μm細化至11μm,為原材的44%;LAZ1110+Sc合金經120°-RT-C4擠製後,晶粒從18μm細化至9.7μm,為原材的54%;LAZ1110+Be合金經120°-RT-C4擠製後,部分區域出現動態再結晶晶粒組織,大小約為5~20μm,LAZ1110+Be&Sc合金經120°-RT-C4擠製後,晶粒大小變化不大。在機械性質部分,最大抗拉強度出現在LAZ1110+Be經120°-RT-C4擠製後,達175.5 MPa,為原材的1.16倍,伸長率仍有69.7%。
四種材料經120°-RT-C4擠製後之試片,施以50、100、150、200及250℃×30min退火處理後,於LAZ1110+Be,250℃×30min退火條件下觀察到大面積的靜態再結晶,晶粒大小約為4.5μm,且費德曼組織消失。而四種材料退火硬度值於50℃呈現下降的趨勢,而後隨著溫度提升而有漸增的趨勢,50-200℃硬度值均呈平緩漸增,至250℃硬度值產生驟增的現象。 | zh_TW |
dc.description.abstract | An unprecedented try of adding Sc and Be elements into Mg-Li alloys in order to enhance their strengths has been carried out and the results will be presented. Four Mg-Li alloys; a bare one (11%Li-1%Al-0.5%Zn), the second with Sc, the third with Be and the fourth with both Sc and Be were prepared by vacuum melting processes. They were then homogenized at 350℃, followed by an extrusion for plates. Microstructures and mechanical properties are studied on this as-extruded sample and those subsequently process by equal channel angular extrusion (ECAE) at room temperature.
The effect of adding Sc element to the LAZ1110 alloy was refining β grains. The addition of Be element produces two micro-structural effects, grain coarsening and Widmanstatten structure. On the mechanical properties, the maximum tensile strength obtained in LAZ1110+Be is 151MPa.This figure is better than the other of three alloys.
LAZ1110 alloy processed under condition, 120°-RT-C4, the size of β grains range from 25μm to 11μm. LAZ1110+Sc alloy processed under condition, 120°-RT-C4, the size of β grains range from 18μm to 9.7μm. LAZ1110+Be alloy processed under condition, 120°-RT-C4, some area of β phase can be find dynamic recrystallization grains. LAZ1110+Be&Sc alloy processed under condition, 120°-RT-C4, the change of β grains were small. On the mechanical properties, LAZ1110+Be alloy processed under condition, 120°-RT-C4,shows the greatest increase in tensile strength about 24.8 MPa. | en_US |
DC.subject | 鎂鋰鋁鋅合金 | zh_TW |
DC.subject | 等通道彎角擠製 | zh_TW |
DC.subject | 微結構 | zh_TW |
DC.subject | 機械性質 | zh_TW |
DC.subject | Mg-Li-Al-Zn alloys | en_US |
DC.subject | Equal channel angular extrusion | en_US |
DC.subject | Microstructure | en_US |
DC.subject | Mechanical properties | en_US |
DC.title | 添加鈹、鈧之LAZ1110鎂鋰合金經等通道彎角擠製後之微結構及機械性質研究 | zh_TW |
dc.language.iso | zh-TW | zh-TW |
DC.title | A study on the Microstructures and Mechanical properties ofLAZ1110 Mg-Li alloy containing Sc and Be after Equal Channel Angular Extrusion | en_US |
DC.type | 博碩士論文 | zh_TW |
DC.type | thesis | en_US |
DC.publisher | National Central University | en_US |