本文選題：連續(xù)變通道直接擠壓 + 耐熱鎂合金��； 參考：《哈爾濱理工大學(xué)》2015年碩士論文

【摘要】：隨著航空航天和汽車等領(lǐng)域?qū)p量化需求的日益漸增，鎂合金作為目前可應(yīng)用的最輕金屬結(jié)構(gòu)材料，擁有廣闊的應(yīng)用前景。但密排六方的晶體結(jié)構(gòu)，使鎂合金在常溫下的滑移系較少，表現(xiàn)為塑性變形能力較差，不利于加工及成形。目前大塑性變形技術(shù)已被證實(shí)是鎂合金晶粒細(xì)化、改善組織均勻性及提高綜合性能的重要途徑之一。但傳統(tǒng)大塑性變形技術(shù)通常需要反復(fù)、多次加載或處理才能達(dá)到預(yù)期效果，工序復(fù)雜、周期長(zhǎng)且更難于實(shí)現(xiàn)工業(yè)化應(yīng)用等瓶頸問題凸現(xiàn)出來。 為此，本文提出了一種可將細(xì)晶制備工序融入到擠壓工藝中的新技術(shù)——連續(xù)變通道直接擠壓法。該方法通過在坯料和芯模之間增設(shè)一定數(shù)量及結(jié)構(gòu)的過渡模而形成一個(gè)連續(xù)變化曲率的型腔通道，金屬流經(jīng)時(shí)受到類似“鐓-拔-鐓”的持續(xù)加載變形作用，劇烈剪切變形可使微觀組織形貌和力學(xué)性能發(fā)生改變，在單道次內(nèi)即可實(shí)現(xiàn)對(duì)擠出制品形/性的一體化調(diào)控。 首先，研究了連續(xù)變通道直接擠壓原理及工藝特點(diǎn)，以此為依據(jù)，設(shè)計(jì)和研制出所需的過渡模結(jié)構(gòu)及形式，推導(dǎo)并建立了N階過渡模的連續(xù)變通道直接擠壓通用的累積應(yīng)變量理論計(jì)算模型，證明了此技術(shù)在總擠壓比不變情況下增加累積應(yīng)變量的可行性；隨后，以耐熱鎂合金ZM6為例，采用數(shù)值模擬和工藝實(shí)驗(yàn)相結(jié)合方法，經(jīng)過渡模數(shù)量及結(jié)構(gòu)對(duì)連續(xù)變通道直接擠壓過程影響的研究結(jié)果表明，與常規(guī)擠壓相比，增設(shè)過渡模擠壓后連續(xù)的剪切變形使擠后制品的動(dòng)態(tài)再結(jié)晶進(jìn)行更加充分，達(dá)到深度細(xì)化晶粒尺寸的實(shí)效，抗拉強(qiáng)度也隨之提高，擠出金屬的變形流動(dòng)均勻性明顯改善，并降低了產(chǎn)生表面開裂缺陷可能性；通過不同過渡模結(jié)構(gòu)及組合模式的調(diào)整可深度挖掘擠壓工藝的細(xì)晶強(qiáng)化能力，如過渡模尺寸或模角等結(jié)構(gòu)設(shè)計(jì)不合理時(shí)，在變通道型腔內(nèi)側(cè)易存在死區(qū)缺陷，這使相應(yīng)階段的實(shí)際變形量與較理論計(jì)算值要小些。 最后，研究了鑄態(tài)和擠壓態(tài)ZM6鎂合金連續(xù)變通道直接擠壓后，分別進(jìn)行固溶、時(shí)效及固溶時(shí)效處理后微觀組織演變規(guī)律的研究結(jié)果表明，擠壓態(tài)ZM6經(jīng)時(shí)效處理后，在晶粒內(nèi)部逐漸有連續(xù)析出相產(chǎn)生，，并隨著時(shí)效時(shí)間逐漸增多；而在固溶時(shí)效處理后，晶粒尺寸則明顯增大。而隨時(shí)間的增加，晶界處由少量不連續(xù)析出相出現(xiàn)，但增幅明顯變緩。 綜上可知，連續(xù)變通道直接擠壓工藝為大塑性變形技術(shù)真正實(shí)現(xiàn)工業(yè)化應(yīng)用提供了實(shí)質(zhì)突破的可能性，并為高性能鎂合金擠壓制品短流程成形技術(shù)的研究提供了重要的科學(xué)依據(jù)。
[Abstract]:With the increasing demand for lightweight in the fields of aerospace and automobile, magnesium alloys, as the most light metal structural materials available at present, have a broad application prospect. However, due to the hexagonal crystal structure, the slip system of magnesium alloy at room temperature is less, and the plastic deformation ability is poor, which is not conducive to processing and forming. At present, the technology of large plastic deformation has been proved to be one of the important ways to refine the grain, improve the microstructure uniformity and improve the comprehensive properties of magnesium alloy. However, the traditional large plastic deformation technology usually needs repeated loading or treatment to achieve the desired effect, the process is complex, the cycle is long and it is more difficult to realize the industrial application. In this paper, a new technology, continuous variable Channel Direct Extrusion, is proposed, which can integrate the fine grain preparation process into the extrusion process. This method forms a continuous cavity channel with varying curvature by adding a certain number and structure of transition modes between the blank and core die, and the metal is subjected to continuous loading and deformation similar to that of "upsetting, pulling and upsetting" as the metal flows through. Severe shear deformation can change the morphology and mechanical properties of the extruded products, and the shape / property of extruded products can be controlled in a single pass. Firstly, the principle and process characteristics of continuous variable channel direct extrusion are studied. Based on this, the structure and form of transition die are designed and developed. The theoretical calculation model of cumulative strain for continuous variable channel direct extrusion of N-order transition die is derived and established. It is proved that this technique is feasible to increase cumulative strain under the condition of constant total extrusion ratio. Then, taking heat-resistant magnesium alloy ZM6 as an example, By using the method of numerical simulation and technological experiment, the effect of the number and structure of the crossing die on the direct extrusion process of the continuous variable channel is studied. The results show that, compared with the conventional extrusion, The continuous shear deformation after extrusion by adding transition die makes the dynamic recrystallization of extruded products more fully, which can achieve the actual effect of deep refinement of grain size, the tensile strength also increases, and the deformation and flow uniformity of extruded metal is obviously improved. The possibility of producing surface cracking defects is reduced, and the fine grain strengthening ability of extrusion process can be deeply excavated by adjusting the structure of different transition die and combination mode, such as the unreasonable design of transition die size or die angle, etc. It is easy to have dead zone defects in the inner side of the variable channel cavity, which makes the actual deformation of the corresponding stage smaller than that of the theoretical calculation. Finally, the microstructure evolution of as-cast and extruded ZM6 magnesium alloys after direct extrusion with continuous variable channels was studied. The results showed that the microstructure evolution of extruded ZM6 magnesium alloy was studied after aging, aging and solution aging treatment, respectively, and the results showed that, after aging treatment, the microstructure evolution of extruded ZM6 magnesium alloy was studied. There are continuous precipitated phases in the grains, which increase with aging time, but the grain size increases obviously after solution aging. However, with the increase of time, a small amount of discontinuous precipitates appear at the grain boundary, but the increase is obviously slower. It can be concluded that the continuous variable channel direct extrusion technology provides the possibility of a real breakthrough in the industrial application of the large plastic deformation technology. It also provides an important scientific basis for the research of short-process forming technology of high-performance magnesium alloy extrusion products.
【學(xué)位授予單位】：哈爾濱理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TG379

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 郭旭濤,李培杰,曾大本;稀土在耐熱鎂合金中的應(yīng)用[J];稀土;2002年02期

2 梁維中 ,吉澤升 ,左鋒 ,洪艷 ,劉洪匯 ,李軍 ,劉洪德;耐熱鎂合金的研究現(xiàn)狀及發(fā)展趨勢(shì)[J];特種鑄造及有色合金;2003年02期

3 王小強(qiáng);李全安;張興淵;;我國(guó)耐熱鎂合金的研究進(jìn)展[J];上海有色金屬;2007年02期

4 謝建昌;李全安;李建弘;張興淵;;耐熱鎂合金及其開發(fā)思路[J];鑄造技術(shù);2008年01期

5 張春香;王利國(guó);吳立鴻;陳培磊;陳海軍;關(guān)紹康;;主要耐熱鎂合金系的研究進(jìn)展[J];材料科學(xué)與工程學(xué)報(bào);2008年04期

6 趙惠;李平倉;黃張洪;王虎年;;耐熱鎂合金綜述[J];輕合金加工技術(shù);2010年04期

7 田樹科;郭學(xué)鋒;崔紅保;黃丹;王英;;耐熱鎂合金的研究進(jìn)展[J];鑄造技術(shù);2011年08期

8 郭旭濤,李培杰,劉樹勛,曾大本;稀土耐熱鎂合金發(fā)展現(xiàn)狀及展望[J];鑄造;2002年02期

9 閆蘊(yùn)琪,張廷杰,鄧炬,周廉;耐熱鎂合金的研究現(xiàn)狀與發(fā)展方向[J];稀有金屬材料與工程;2004年06期

10 張靜,潘復(fù)生,李忠盛;耐熱鎂合金材料的研究和應(yīng)用現(xiàn)狀[J];鑄造;2004年10期

相關(guān)會(huì)議論文 前7條

1 曲迎東;邱克強(qiáng);馬廣輝;李榮德;;耐熱鎂合金的研究現(xiàn)狀與趨勢(shì)[A];2012年全國(guó)地方機(jī)械工程學(xué)會(huì)學(xué)術(shù)年會(huì)論文集（《機(jī)械》2012增刊）[C];2012年

2 李建弘;李全安;謝建昌;王小強(qiáng);張興淵;;稀土耐熱鎂合金的開發(fā)與應(yīng)用[A];2007高技術(shù)新材料產(chǎn)業(yè)發(fā)展研討會(huì)暨《材料導(dǎo)報(bào)》編委會(huì)年會(huì)論文集[C];2007年

3 黃文剛;劉波;劉建才;李曉青;;耐熱鎂合金研究進(jìn)展及在汽車上的應(yīng)用[A];2012重慶汽車工程學(xué)會(huì)年會(huì)論文集[C];2012年

4 黃文剛;劉波;劉建才;李曉青;;耐熱鎂合金研究進(jìn)展及在汽車上的應(yīng)用[A];西南汽車信息：2012年下半年合刊[C];2012年

5 張磊;龔明;彭良明;;Mg-Gd-Y-Sn-Zr高強(qiáng)耐熱鎂合金的微觀結(jié)構(gòu)與力學(xué)性能[A];2012年海峽兩岸破壞科學(xué)/材料試驗(yàn)學(xué)術(shù)會(huì)議論文摘要集[C];2012年

6 任文亮;李全安;石雅靜;張興淵;;稀土Nd在耐熱鎂合金中的應(yīng)用[A];2009中國(guó)功能材料科技與產(chǎn)業(yè)高層論壇論文集[C];2009年

7 艾延齡;劉江文;羅承萍;;含Ca、Si鎂合金的力學(xué)性能分析[A];2004年中國(guó)材料研討會(huì)論文摘要集[C];2004年

相關(guān)博士學(xué)位論文 前2條

1 文麗華;固相再生ZM6耐熱鎂合金組織和性能研究[D];哈爾濱理工大學(xué);2009年

2 薛山;含Nd耐熱鎂合金顯微組織和性能的研究[D];東南大學(xué);2006年

相關(guān)碩士學(xué)位論文 前10條

1 遲大釗;稀土及鋯、鈣對(duì)耐熱鎂合金組織及性能的影響研究[D];哈爾濱理工大學(xué);2004年

2 孫巖;發(fā)動(dòng)機(jī)缸體用耐熱鎂合金的研究[D];太原理工大學(xué);2013年

3 汪洋;含稀土耐熱鎂合金擠壓工藝及其組織與性能研究[D];華東理工大學(xué);2013年

4 耿寧寧;幾種耐熱鎂合金的組織及性能[D];沈陽工業(yè)大學(xué);2013年

5 徐道芬;耐熱鎂合金壓蠕變行為的研究[D];西華大學(xué);2008年

6 張青輝;耐熱鎂合金的組織與高溫性能[D];四川大學(xué);2007年

7 楊剛;鈣對(duì)AE系耐熱鎂合金凝固行為的影響[D];西華大學(xué);2013年

8 黃華勇;耐熱鎂合金的研究[D];重慶大學(xué);2005年

9 劉洋;AX系耐熱鎂合金組織和性能的研究[D];江西理工大學(xué);2010年

10 楊成亮;Mg-Sn-Si耐熱鎂合金的研究[D];沈陽工業(yè)大學(xué);2014年

本文編號(hào)：1858419