钛合金舵体超塑成形_扩散连接工艺研究

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南京航空航天大学硕士学位论文
目 录
第一章 绪论 .......................................................................................................................................... 1 1.1 引言 ......................................................................................................................................... 1 1.2 超塑成形/扩散连接工艺基本理论......................................................................................... 2 1.2.1 超塑性成形技术........................................................................................................... 2 1.2.2 扩散连接技术............................................................................................................... 3 1.3 超塑成形/扩散连接工艺原理及研究进展............................................................................. 5 1.3.1 超塑成形/扩散连接工艺原理...................................................................................... 5 1.3.2 超塑成形/扩散连接工艺研究进展.............................................................................. 8 1.3.3 超塑成形/扩散连接技术发展趋势............................................................................ 10 1.4 钛合金激光焊接及超塑成形/焊接组合技术的研究进展 ................................................... 11 1.5 有限元法在超塑成形工艺中的应用 .................................................................................... 12 1.6 课题来源及主要研究内容.................................................................................................... 12 1.6.1 课题来源..................................................................................................................... 12 1.6.2 主要研究内容............................................................................................................. 13 第二章 课题研究任务与总体研究方法............................................................................................. 14 2.1 课题研究任务........................................................................................................................ 14 2.2 实验材料 ............................................................................................................................... 14 2.3 总体实验方案........................................................................................................................ 15 2.4 实验设备 ............................................................................................................................... 16 2.4.1 激光焊接设备............................................................................................................. 16 2.4.2 拉伸实验设备............................................................................................................. 17 2.4.3 热成形设备................................................................................................................. 17 2.4.4 真空超塑成形/扩散连接设备.................................................................................... 18 2.4.5 超塑成形气压加载设备 ............................................................................................. 18 2.4.6 微观组织观测设备..................................................................................................... 19 2.5 实验结果分析........................................................................................................................ 19 第三章 舵体内部筋条布置及芯板超塑性成形有限元模拟 ............................................................. 20 3.1 引言 ....................................................................................................................................... 20 3.2 舵体内部筋条布置方案........................................................................................................ 20
January, 2013
承诺书
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Research on Superplastic Forming and Diffusion Bonding Technology of TC4 Titanium Alloy Rudder
A Thesis in Aerospace Manufacture Engineering by Wang Dagang Advised by Professor Zhang Yihua Submitted Βιβλιοθήκη Baidun Partial Fulfillment for the Degree of Master of Engineering
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钛合金舵体超塑成形/扩散连接工艺研究
ABSTRACT
Superplastic forming and diffusion bonding (SPF/DB) generally can be used to manufacture integral multi-sheet structure within a single forming process. The formed structure is characteristic by good bending rigidity, remarkably load-bearing stability, superior surface quality , excellent shape precision and light structure weight, with good energy absorption and fatigue resistance ability. Moreover, the SPF/DB process reduces the cost dramatically. Hence, SPF/DB has become a important and preferred method to manufacture aerofoil parts. However, the traditional process of SPF/DB has a series of disadvantages, including the difficulty of coating stop-off, long time thermal exposure and low yield of the product. To solve the above problems, laser welding can be introduced to reform the traditional SPF/DB method， improving the mechanical properties and increasing the yield . Therefore, it is extremely important and practically valuable to do some research on the SPF/DB combined with laser welding for forming multi-sheet structure of aerofoil parts. In this thesis, research on the laser welding and SPF/DB technology for Ti-6Al-4V titanium alloy rudder was carried out, and the sample of four layer structure was fabricated successfully. The main researches are as follows: Based on the theory of SPF/DB, with other related theories, the SPF process of the core-sheet was simulated in ABAQUS using the nonlinear finite element method. Then, the distribution of thickness and stress condition were predicted and the pressure-time control curve under iso-strain rate was obtained, which provide reference for the subsequent experiments. The laser penetration welding process for two sheets of Ti-6Al-4V titanium alloy was studied, the optimal welding parameters were obtained, and the core sheets of four-layer structure were successfully welded. Then, the SPF/DB experiment was carried out to fabricate the rudder. Quality of the forming rudder was tested. It reveals that the performance of the rudder well meet the requirement. The inner stiffeners are completely vertical and the distribution of thickness is quite homogeneous, what is more, the bonding percent exceeds 95%. Although microstructure investigation shows that the grain size grows up evidently, it is smaller than the grain size of traditional process. The result shows that the proposed process is feasible. It solves the problems of the traditional SPF/DB process and extends the application of SPF/DB process. Keywords: Ti-6Al-4V titanium alloy rudder, laser welding, superplastic forming/diffusion bonding, multi-sheet structure, finite element simulation
作者签名： 日 期：
南京航空航天大学硕士学位论文
摘 要
超塑成形/扩散连接（Superplastic forming/diffusion bonding，简称 SPF/DB）技术可以在一 次成形过程中制造多层板复合整体结构，成形的多层板结构具有弯曲刚度大、承载稳定性高、 表面和外形质量好、结构重量小以及良好的能量吸收和疲劳性能等优点，并且大大降低了生产 成本，故目前已成为制造飞行器舵翼类零件的重要方法。 然而，传统的超塑成形/扩散连接工艺存在着一系列问题，主要表现在：止焊剂涂敷困难、 成形零件热暴露时间长及零件成品率低等。用激光焊接代替一部分扩散连接的方法能够解决传 统工艺的不足，大大提高制件成品率及成形件的力学性能，因此开展激光焊接与超塑成形/扩散 连接组合工艺的研究，具有重要意义。本文针对某 TC4 钛合金舵体零件进行深入的激光焊接、 超塑成形/扩散连接的工艺研究，主要进行了如下研究： 基于材料超塑成形和扩散连接的基本原理，结合相关理论，利用有限元软件 ABAQUS 对 某 TC4 钛合金舵体的超塑成形过程进行了模拟，对构件的壁厚分布、应力情况做出了预测，获 得了优化的等应变速率下的压力-时间曲线，为超塑成形/扩散连接工艺的气压加载提供了参考 依据。 在对钛合金舵体超塑成形过程进行模拟仿真分析基础上，研究了两层 0.6mm 厚的 TC4 钛 合金板的激光穿透焊接工艺，确定了优化的焊接参数，并成功焊接了四层板结构的中间两层芯 板。随后进行了四层结构的超塑成形/扩散连接工装准备，并进行了相关的超塑成形 /扩散连接 试验，研制成功了合格的舵体样件。 对舵体零件的质量检测表明：舵体零件外观形貌完好，内部加强筋完全直立，壁厚分布均 匀，扩散连接区域的微观组织没有明显长大，总体焊合率达 95%以上。 通过以上研究表明， 本文采用的激光预焊芯板的超塑成形/扩散连接的新工艺是制造中空复 合夹层结构的一种可行方法，能够解决传统超塑成形/扩散连接工艺中存在的诸多问题，具有很 大优势及发展前景。 关键词：TC4 钛合金舵体，激光焊接，超塑成形/扩散连接，多层结构，有限元模拟
中图分类号: TG457.19 学科分类号: 082503
论文编号：1028705 13-S225
硕士学位论文
钛合金舵体超塑成形/扩散连接 工艺研究
研究生姓名 学科、专业 研究方向 指导教师
王大刚 航空宇航制造工程 材料成形新技术 张益华 副教授
南京航空航天大学
研究生院 机电学院
二〇一三年一月
Nanjing University of Aeronautics and Astronautics The Graduate School College of Mechanical & Electrical Engineering