本文選題：等徑角擠壓 + 超細(xì)晶純銅�。� 參考：《哈爾濱工業(yè)大學(xué)》2017年碩士論文

【摘要】：微系統(tǒng)技術(shù)以及微機(jī)電系統(tǒng)的迅速崛起,帶動(dòng)當(dāng)前工業(yè)朝著小型化、微型化的方向發(fā)展。而利用傳統(tǒng)工業(yè)材料生產(chǎn)微型零件時(shí),由于晶粒尺寸與微型零件的某一維度尺寸相當(dāng),出現(xiàn)明顯的尺寸效應(yīng),從而在實(shí)際生產(chǎn)中影響成形件最終的尺寸精度,提高生產(chǎn)成本,且降低了生產(chǎn)效率。研究表明,利用超細(xì)晶材料生產(chǎn)微型零件時(shí),上述缺點(diǎn)可得到明顯改善,極大的提高了生產(chǎn)效率和產(chǎn)品質(zhì)量,為微成形技術(shù)的發(fā)展鋪平了道路。與傳統(tǒng)的壓縮實(shí)驗(yàn)相比,T型微鐓擠實(shí)驗(yàn)具有模具結(jié)構(gòu)簡(jiǎn)單、操作方便等優(yōu)勢(shì),金屬內(nèi)部同時(shí)進(jìn)行擠壓變形和壓縮變形,材料內(nèi)部變形劇烈,且可利用同一組模具對(duì)不同尺寸的試樣進(jìn)行實(shí)驗(yàn)。因此,本文首先利用等徑角擠壓工藝制備超細(xì)晶純銅材料,利用Deform-3D有限元分析軟件模擬T型微鐓擠變形行為,并在室溫及高溫條件下對(duì)超細(xì)晶純銅進(jìn)行T型微鐓擠實(shí)驗(yàn),分析在熱力場(chǎng)耦合作用下超細(xì)晶純銅微觀組織演變規(guī)律。在T型微鐓擠變形過程中,根據(jù)金屬材料的流動(dòng)規(guī)律,可將變形分成兩個(gè)階段:第一階段,試樣向凹模型腔內(nèi)部的流動(dòng)速度大于向凹模兩側(cè)的流動(dòng)速度,此時(shí)材料以擠壓變形為主,壓縮變形為輔;第二階段,試樣向凹模兩側(cè)測(cè)流動(dòng)速度大于向型腔內(nèi)部的流動(dòng)速度,此時(shí)材料以壓縮變形為主,擠壓變形為輔。通過有限元分析及實(shí)驗(yàn)結(jié)果表明:凹模型腔參數(shù)對(duì)T型微鐓擠變形時(shí)的變形力、擠壓筋高度及高寬比λ有顯著影響,凹模表面粗糙度對(duì)變形第一階段的變形力影響不大,但在變形的第二階段,變形力隨表面粗糙度的增加而增大;凹模圓角半徑和開口角度對(duì)整個(gè)T型微鐓擠變形中的變形力都有顯著影響,隨著凹模圓角半徑和開口角度的增加而變大;擠壓筋高度及高寬比λ隨凹模表面粗糙度、圓角半徑及開口角度的增大而線性降低。隨著變形溫度的升高,由于變形時(shí)超細(xì)晶純銅發(fā)生動(dòng)態(tài)回復(fù)和動(dòng)態(tài)再結(jié)晶,變形力逐漸下降;當(dāng)變形溫度低于200℃時(shí),超細(xì)晶純銅內(nèi)部發(fā)生動(dòng)態(tài)回復(fù),變形力和高寬比緩慢降低,但是擠壓筋高度緩慢增大,晶粒長(zhǎng)大不明顯;當(dāng)變形溫度高于250℃時(shí),變形力迅速降低,擠壓筋高度和高寬比λ迅速增大,晶粒長(zhǎng)大明顯,當(dāng)變形溫度達(dá)到400℃時(shí),平均晶粒尺寸由0.44μm長(zhǎng)大到3.4μm。
[Abstract]:The rapid rise of micro system technology and microelectromechanical system has led to the development of miniaturization and miniaturization in the current industry. While using traditional industrial materials to produce micro parts, the size of grain size corresponds to a dimension size of the micro parts, which has obvious size effect, which affects the final parts in actual production. The size accuracy improves the production cost and reduces the production efficiency. The research shows that the above shortcomings can be improved obviously, greatly improving the production efficiency and product quality, and paved the way for the development of micro forming technology. Compared with the traditional compression experiment, the T micro upsetting experiment has a mold. The structure is simple, the operation is convenient and so on. The internal deformation and compression deformation of the metal are simultaneously carried out. The internal deformation of the material is intense, and the same group of dies can be used to test the samples of different sizes. Therefore, first of all, the superfine crystal pure copper material is prepared by the equal diameter angle extrusion process, and the Deform-3D finite element analysis software is used to simulate the T microfiber. The behavior of upsetting and extrusion deformation was carried out at room temperature and high temperature. The micro upsetting extrusion experiment of ultrafine crystal copper was carried out at the condition of room temperature and high temperature. The microstructure evolution law of ultrafine crystal copper under the coupling of thermal field was analyzed. In the process of T micro upsetting and extrusion, the deformation can be divided into two stages according to the flow law of metal material. The first stage, the specimen to the concave model cavity The internal flow velocity is greater than the flow velocity to the two sides of the die. At this time, the material is dominated by extrusion deformation and the compression deformation is supplemented. In the second stage, the flow velocity of the sample to the concave die is greater than that of the inner cavity. At this time, the material is mainly compressed and the extrusion deformation is supplemented. The finite element analysis and experimental results show that the die is a concave die. The parameters of the cavity have significant influence on the deformation force, the height of the extruding bar and the ratio of the height to width. The surface roughness of the die has little effect on the deformation force in the first stage of the deformation, but in the second stage of the deformation, the deformation force increases with the increase of the surface roughness; the circular corner radius and the opening angle of the die have a small upsetting and extrusion deformation of the whole T type. With the increase of the radius of the concave die and the angle of the opening, the height of the extruding bar and the ratio of the height to width are linearly decreased with the increase of the surface roughness, the radius of the circle and the angle of the opening. With the increase of deformation temperature, the dynamic recovery and dynamic recrystallization of the superfine crystal copper are formed as the deformation temperature rises. When the deformation temperature is below 200 c, the internal dynamic recovery occurs in the ultrafine crystal pure copper, the deformation force and the ratio of height to width decrease slowly, but the height of the extruding bar increases slowly and the grain growth is not obvious. When the deformation temperature is higher than 250, the deformation force decreases rapidly, the height and width ratio of the extruding rib increase rapidly, and the grain growth is obvious. When the grain grows obviously, when the grain grows, the grain grows obviously. When the grain grows, the grain grows obviously. When the grain grows, the grain grows obviously. When the grain grows, the grain grows obviously, when the grain grows, the grain grows obviously. When the shape temperature reaches 400 degrees, the average grain size grows from 0.44 m to 3.4 m..

【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TG379;TG146.11
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本文編號(hào)：1795007