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  本文關鍵詞： 筒形件 多道次單向及交叉旋壓 3A21鋁合金 晶體塑性 變形織構　出處：《哈爾濱工業(yè)大學》2017年碩士論文　論文類型：學位論文

【摘要】：筒形件旋壓是典型的局部加載成形工藝,具有省料、成形性能好、工裝簡單等優(yōu)點,是制造大型薄壁無縫筒形件的有效方法,已廣泛用于航天、航空、兵器、艦船和機械等工業(yè)領域。由于旋壓變形過程非常復雜,影響因素眾多,到目前為止,大量的旋壓技術研究工作仍定位于零件成形,旋壓缺陷和幾何精度控制等方面,零件力學性能控制方面考慮得較少。晶體學織構能對金屬材料力學性能產(chǎn)生重大影響,織構也就成為控制材料力學性能的重要手段之一。強力旋壓過程中金屬產(chǎn)生劇烈的塑性流動,形成特定變形織構,從而影響到旋壓件的力學性能。本文將以經(jīng)過退火處理的擠壓無縫3A21鋁合金管材,進行多道次單向及交叉旋壓實驗,并進行筒形件的力學性能和旋壓織構研究;采用ABAQUS對筒形件旋壓過程進行相應的有限元模擬,并利用用戶材料子程序VUMAT提取旋壓筒形件的變形歷史,然后再通過UMAT實現(xiàn)率相關的晶體塑性本構關系,建立多晶體模型,通過擬合簡單壓縮應力應變曲線確定室溫3A21鋁合金的滑移系剪切變形參數(shù),將提取的變形梯度歷史并加載到多晶體模型上,基于晶體塑性理論,實現(xiàn)室溫3A21鋁合金筒形件多道次不同方式旋壓變形織構的模擬。進行模擬織構與實測織構的比較。進行多道次旋壓實驗后,觀察旋壓件微觀組織的演化:多道次旋壓過程中少量第二相始終彌散分布在晶界處,其含量不影響晶體學織構的統(tǒng)計。當旋壓到第2道次后,晶粒在ND方向近似于均勻分布,晶粒沿RD方向和TD方向等比例拉長。從第4道次到低8道次,晶粒主要沿著RD方向伸長形成長條狀的晶粒,沿TD方向也存在一定的拉長,隨著晶粒的細化形成纖維狀;從力學性能變化規(guī)律來看,對于交叉旋壓,旋壓件環(huán)向壓縮屈服強度要高于軸向壓縮屈服強度,旋壓件環(huán)向抗拉強度與軸向抗拉強度并沒有產(chǎn)生太大的差距,環(huán)向抗拉強度略高于軸向抗拉強度�？芍徊嫘龎合鄬τ趩蜗蛐龎�,有效調控了晶粒取向,提高了筒形件變形抗力。通過對3A21鋁合金筒形件多道次單向與交叉旋壓變形三維有限元模擬,分析筒形件旋壓后的外表面和軸截面的應力應變分布,發(fā)現(xiàn)筒形件旋壓由于局部加載和變形周期性疊加的特點,筒形件旋壓變形使材料承受方向不斷變化的拉伸、壓縮和剪切的復合變形。對比多道次旋壓有限元模擬獲得的模擬織構與實測織構,分析旋壓晶粒取向演化規(guī)律:變形開始時,單向與交叉旋壓的晶體取向形成明顯{110}112織構,隨著減薄率的增加,晶粒取向逐漸靠近難變形相位,到第4、6、8道次,金屬取向不再是單一的織構,而是逐漸形成{110}112、{112}111、{123}634等類型的織構。我們還發(fā)現(xiàn),在同一變形量下,材料的織構類型近似等同,單向旋壓的織構分布較交叉旋壓相對彌散,相對交叉旋壓強度較低,因此交叉旋壓具有較好的調控晶粒取向的作用,提高了筒形件變形抗力。
[Abstract]:Cylinder spinning is a typical local loading forming process, which has the advantages of saving material, good formability, simple tooling and so on. It is an effective method for manufacturing large thin-walled seamless cylindrical parts. It has been widely used in aerospace, aviation and weapons. As the process of spinning deformation is very complex and there are many influencing factors, up to now, a lot of research work on spinning technology is still focused on parts forming, spinning defects and geometric precision control, etc. The control of mechanical properties of parts is less considered. The crystallographic texture can have a significant effect on the mechanical properties of metal materials. Texture has become one of the most important means to control the mechanical properties of materials. In order to affect the mechanical properties of spinning parts, this paper will carry out multi-pass unidirectional and cross-spinning experiments with annealed seamless 3A21 aluminum alloy tubes, and study the mechanical properties and spinning texture of cylindrical parts. The ABAQUS is used to simulate the spinning process of the cylinder, and the deformation history of the spinning cylinder is extracted by the user material subroutine VUMAT, and then the polycrystalline model is established by using the constitutive relation of crystal plasticity related to the realization rate of UMAT. The slip system shear deformation parameters of room temperature 3A21 aluminum alloy were determined by fitting the simple compression stress-strain curve. The extracted deformation gradient history was loaded into the polycrystalline model and based on the theory of crystal plasticity. The simulation of multi-pass deformation texture of room temperature 3A21 aluminum alloy cylinder is realized. The comparison between the simulated texture and the measured texture is carried out. After the multi-pass spinning experiment, The microstructure evolution of spinning parts is observed: a small amount of second phase is distributed at grain boundaries throughout the multi-pass spinning process, and its content does not affect the statistics of crystallographic texture. When spinning to the second pass, the grain distribution is approximately uniform in ND direction. From the 4th pass to the low 8 pass, the grains are mainly elongated along the Rd direction and elongated along the TD direction, forming fibrous with the refinement of the grains. According to the law of mechanical properties, for cross spinning, the yield strength of annular compression is higher than that of axial compression, and there is not much difference between the annular tensile strength and axial tensile strength. The circumferential tensile strength is slightly higher than the axial tensile strength. The deformation resistance of the cylindrical part is improved. The stress and strain distribution of the outer surface and axial section of the cylindrical part after spinning is analyzed by simulating the multi-pass unidirectional and cross-spinning deformation of the 3A21 aluminum alloy tube by three dimensional finite element method. It is found that due to the characteristic of local loading and periodic superposition of deformation, the spinning deformation of the cylindrical part makes the material endure the continuously changing tensile direction. Compression and shear composite deformation. Compared with the simulated texture obtained by multi-pass spinning finite element simulation and the measured texture, the evolution law of spinning grain orientation was analyzed: at the beginning of deformation, the crystal orientation of unidirectional and cross-spinning formed obvious {110} 112 texture. With the increase of thinning rate, the grain orientation is closer to the difficult deformation phase. At the 4th pass, the metal orientation is no longer a single texture, but gradually forms {110} 112, {112} 111, {123} 634 and other types of texture. We also find that under the same deformation amount, the grain orientation is not only a single texture, but also forms a texture of {110} 112, {112} 111, {123} 634 and so on. The texture type of the material is approximately the same, and the texture distribution of unidirectional spinning is relatively dispersed and the relative cross spinning strength is lower than that of cross spinning. Therefore, cross spinning has a better effect on regulating grain orientation and improving the deformation resistance of cylindrical parts.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TG306

【參考文獻】

相關期刊論文 前10條

1 鄒小堤;黃照;桂林;張明慶;何毅斌;;大型數(shù)控強力旋壓機關鍵零件制造工藝研究[J];武漢理工大學學報(交通科學與工程版);2012年04期

2 趙升噸;趙承偉;王君峰;林文捷;;現(xiàn)代旋壓設備發(fā)展趨勢的探討[J];中國機械工程;2012年10期

3 侯紅亮;余肖放;王耀奇;;國內旋壓設備及其相關技術的發(fā)展與現(xiàn)狀[J];鍛壓裝備與制造技術;2009年04期

4 賀彤;劉沿東;蔣奇武;左良;;異步軋制對IF鋼冷軋及再結晶織構的影響[J];東北大學學報(自然科學版);2008年04期

5 徐平光;友田陽;;原位中子衍射材料表征技術的進展[J];金屬學報;2006年07期

6 江樹勇;薛克敏;李春峰;張軍;;基于神經(jīng)元網(wǎng)絡的薄壁筒滾珠旋壓成形缺陷診斷[J];鍛壓技術;2006年03期

7 鄺衛(wèi)華;夏琴香;阮鋒;;鋁合金薄壁管縮徑旋壓成形缺陷及工藝分析[J];輕合金加工技術;2006年04期

8 李眉娟,勾成,張百生,陳東風;材料織構的中子衍射測量[J];原子能科學技術;2004年S1期

9 張克實;多晶體變形、應力的不均勻性及宏觀響應[J];力學學報;2004年06期

10 張光,張克實,馮露;有限變形下多晶晶體塑性模型算法及應用[J];應用力學學報;2004年01期

，

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