DEFORM铝合金压缩变形过程孔洞缺陷闭合的研究.docVIP

DEFORM铝合金压缩变形过程孔洞缺陷闭合的研究 摘要：本论文利用DEFORM有限元软件对镦粗变形过程中圆柱体坯料内部孔洞闭合过程进行了模拟研究，并对坯料内部不同位置处及不同形状的孔洞闭合过程进行了计算，得到其闭合规律，定量给出了孔洞闭合时所需的临界变形程度。模拟结果表明：不同位置处孔洞的闭合具有相同的过程，且孔洞尺寸变化与变形程度之间近似成线性关系。随变形程度的增大，孔洞闭合程度均增大，但不同位置处孔洞闭合程度存在差异。对于不同形状的孔洞，四面体孔最难闭合，为所有孔洞闭合所需临界压变形程度的上限值。随后,通过物理实验对上述数值模拟结果进行了验证,模拟结果与实验结果基本一致，从而验证了本文采用的有限元模拟法在分析镦粗变形过程中孔洞闭合方面的可行性和可靠性。6506 关键词：孔洞缺陷；孔洞闭合；数值模拟；铝合金 Aluminum compression process of closing holes Abstract：In this paper, the finite element software DEFORM upsetting deformation process billet cylinder internal voids closing process was simulated, and the billet at different locations inside the holes of different shapes and closing process was calculated to obtain its closed rule, quantitatively the hole is closed and the critical degree of deformation. The results showed that: the closed position of holes with the same procedure, and the pore size between the change and the degree of deformation is approximately linear. With the deformation increases, the degree of closure holes are increased, but the degree of closure holes at different locations differ. The different shapes of holes, closed tetrahedral hole difficult, closed holes required for all critical pressure upper limit of the degree of deformation. Subsequently, respectively, through physical simulation and experimental verification of these two aspects of numerical simulation results verify, validate the results are basically the same, which proves this paper, the finite element method in the analysis of the deformation process upsetting aspects of the feasibility and closed pores reliability. 3.4.1 实验设备22 3.4.2 Al6061实验验证24 4 结论29 致谢30 参考文献31 1 绪论 1.1 铝合金基本简介 1.1.1 基本信息 铝合金（图1.1）以铝为基的合金总称。主要合金元素有铜、硅、镁、锌、锰，次要合金元素有镍、铁、钛、铬、锂等。 铝合金是工业中应用最广泛的一类有色金属结构材料，在航空、航天、汽车、机械制造、船舶及化学工业中已大量应用。随着近年来科学技术以及工业经济的飞速发展，对铝合金焊接结构件的需求日益增多，使铝合金的焊接性研究也随之深入。铝合金的广泛应用促进了铝合金焊接技术的发展，同时焊接技术的发展又拓展了铝合金的应用领域，因此铝合金的焊接技术正成为研究的热点之一。 纯铝的密度小（rho;=2.7g/cm3），大约是铁的 1/3，熔点低（660℃），铝是面心立方结构，故具有很高的塑性（delta;:32~40%，psi;:70~90%），易于加工，可制成各种型