TA15合金的超塑性及其应用研究.pdf

- I - 摘 要 TA15 合金是一种近α型钛合金，其半成品有薄板、厚板、棒材，具有较好的综合力学性能和工艺性能然而，近几年国内外对于钛合金超塑性的研究主要集中在βα+两相钛合金上，对α和近α型钛合金的研究较少，而对近α型 TA15 合金的技术研究也并不多，因此，研究 TA15 合金的超塑性并指导其在工程方面的应用是很具有现实意义的 此外，由于 TA15 合金具有成形温度范围窄，局部容易过热，成形载荷较大等特点，给成形带来了较大困难，为了更好地理解 TA15 合金飞机隔框在成形过程中的变形规律及其影响因素，避免大量人力、物力和财力的浪费，在研究的后期阶段，采用有限元技术对飞机隔框的等温锻造过程进行了模拟，为预测成形过程中的变形行为、可能产生的缺陷和确定最佳工艺参数等提供了理论依据 在 Visual Basic 环境下编写了超塑性拉伸控制软件的子程序，该控制软件能很好地实现对拉伸机的控制、实验过程中的数据采集、分析和处理，并具有绘制实时监控曲线等功能最后，将各子程序整合后，形成了一套完整、高效的超塑性研究方法 随后，本文对TA15 合金的超塑性进行了系统研究，在变形温度为 850℃、900℃和 950℃，分别采用最大m值法、应变速率循环法和等应变速率法研究了工艺参数对流动应力、m值及其超塑性的影响，实验结果表明，由应变速率循环法分析得到的最佳应变速率可信度较高。

TA15 合金最佳的变形工艺参数为：温度900℃，应变速率 1×10-4s-1，得到的延伸率为 926%在同样的温度下，采用最大m值法可获得延伸率为 963%的超塑性 最后，根据实验得出 TA15 合金高温变形的应力-应变曲线，将该曲线输入到有限元软件中，并对 TA15 合金飞机隔框的超塑性等温锻造过程进行了三维变形模拟研究了变形工艺参数，包括上模速度、摩擦等因素对零件成形过程中应力、应变的影响，计算了各种变形条件下的位移-载荷曲线研究结果表明，在摩擦因子同为 0.3 的条件下，上模速度 0.001mm/s，0.01mm/s 和 0.1mm/s 对应的最大载荷吨位分别为 1647t、5331t 和 23474t上述研究为 TA15 合金飞机隔框的等温锻造工艺的优化设计及质量控制提供了理论和技术上的支持 关键词：TA15 合金，超塑性，控制系统，等温锻造，数值模拟 - II - Abstract Abstract TA15 Alloy is a near-α Titanium Alloy, its semi-manufactured goods include sheet metal, thick board, stick, and have good compound mechanical and process characteristic. However, the research of superplasticity was mainly focused on the βα+ Titanium Alloy at home and abroad, and even less on the α-phase TA15 alloy. Therefore, it is meaningful to carry on the superplastic research of TA15 alloy and then instruct its engineering application. Besides，The deformation of the TA15 alloy is difficult because of narrow process window, local overheating and high resistance of deformation. To understand the deformation behavior and the effect of process parameters on deformation of the TA15 alloy during high temperature forming and decrease wasting of time, man power and cost, in the final phase of the research, FEM technology was adopted in simulating the isothermal forging process of airplane frame, which can provide scientific foundation for predicting whether defects occurring or not and determining the optimal process parameters. Some subprograms were compiled and debugged under Visual Basic environment for the controlling system of superplastic drawing, the program could fulfill the task of controlling the drawing machine, acquiring, analyzing and processing data generated during the experiment, and can even draw real time supervising curves, thus a complete, effective method of superplastic research was formed after the subprograms were integrated. Subsequently, the superplastic deformation behavior of TA15 alloy has been investigated. The influence of processing parameters on the flow stress and strain rate sensitivity (m value) and its superplasticity was studied by adopting the Maximum m, Strain Rate Cycling (SRC) and Constant Strain Rate method, and the temperature was 850℃, 900℃, 950℃ respectively, the results showed that the best strain rate gained from the SRC method is reliable. Its best deformation temperature is 900℃, and the strain rate is about 1×10-4s-1, the elongation reaches 926% under this experiment condition. Meanwhile, its elongation reaches 963% when adopted the Maximum m method at the same temperature. Finally, Based on the experiment, the stress-strain curves of TA15 alloy during - III - high temperature deformation has been established, and the curves was integrated into the FEM software, then a couple simulation of deformation has been carried out for the airplane frame isothermal superplastic forging of TA15 alloy. The effect of process parameters, including the punch velocity, the friction on the stress and strain during isothermal forging has been studied and load-journey curves with different parameters have been calculated. The results showed that the maximum load tonnage is 1647t, 5331t, 23474t, and corresponding punch velocity is 0.001mm/s, 0.01mm/s, 0.1mm/s respectively when the friction factor is 0.3. This work provides the theory and technique foundation for implementing process optimized design and quality control scheme of TA15 alloy airplane frame isothermal forging process. KEYWORDS: TA15 Titanium Alloy, Superplasticity, Controlling System, Isothermal Forging, Numerical Simulation KEYWORDS: TA15 Titanium Alloy, Superplasticity, Controlling System, Isothermal Forging, Numerical Simulation 南昌航空大学硕士学位论文原创性声明 本人郑重声明：所呈交的硕士学位论文，是我个人在导师指导下，在南昌航空大学攻读硕士学位期间独立进行研究工作所取得的成果。

尽我所知，论文中除已注明部分外不包含他人已发表或撰写过的研究成果对本文的研究工作做出重要贡献的个人和集体，均已在文中作了明确地说明并表示了谢意本声明的法律结果将完全由本人承担 签名： 日期： 南昌航空大学硕士学位论文使用授权书 本论文的研究成果归南昌航空大学所有，本论文的研究内容不得以其它单位的名义发表本人完全了解南昌航空大学关于保存、使用学位论文的规定，同意学校保留并向有关部门送交论文的复印件和电子版本，允许论文被查阅和借阅本人授权南昌航空大学，可以采用影印、缩印或其他复制手段保存论文，可以公布论文的全部或部分内容同时授权中国科学技术信息研究所将本学位论文收录到《中国学位论文全文数据库》 ，并通过网络向社会公众提供信息服务 （保密的学位论文在解密后适用本授权书） 签名： 导师签名： 日期： - 73 - 南昌航空大学硕士学位论文 第 1 章 绪论 - 1 - 第 1 章 绪论 1.1 引言 我国航空航天、国防工业的发展必须有强大的钛产业的支持。

而钛又是一种非常年轻的材料，登上工业舞台仅约半个世纪，现在还处于发展的幼年时期它目前的产量大约相当于 150 年前的世界钢产量我国钛产业的发展虽然比美。