航空用高强铝合金大型复杂构件蠕变时效形性协同制造的科学基础

Age forming technology has been developed as a new forming method in recent years to manufacture large integral panels in modern aircraft and aerospace area. It has a broad application prospects in large airliner and large military aerotransport of our country. Due to the lack of research on the key scientific problems of this technology involved in the forming mechanism and the lack of understanding on relative technique principle, which still unable to achieve its industrial applications in China. .Panel components of 2000 series high strength aluminium alloys were chosen as research object. Study the complicated manufacturing process, which includes precipitation behaviour of second phase under complex heat and force fields during age forming process and the decided performance formation mechanism, and also the effecting law of precipitates states on creep and stress relaxation behaviour and the decided shape formation mechanism, to discover the dynamic alternative and coupling activation mechanism between second phase precipitation and creep and stress relaxation. Then to build a set of unified constitutive equations based on the forming mechanism of age forming under complex heat and force conditions. Study the changing mechanism from elastic deformation to visco-plastic one for complex double curvature panel components during age forming process and its association rules with spring-back, and then set up a multi-scale simulation platform for the whole age forming process and relative spring-back prediction method, to clarify the influence law of different match pattern of heat and force in space and time fields on the forming and growing of precipitates, creep and stress relaxation behaviour. In the end, to develop the shape and property cooperative manufacturing principle and technique models for age forming of large panel components under multilevel heat and force combined fields.

时效成形技术是为制备大型整体壁板类构件近年发展起来的一项新技术。在我国大型客机、大型军用运输机研制中具有广泛的应用前景，但因缺乏对该技术核心科学问题的研究及技术规律的认识，无法实现工程化应用。.本项目以2×××系高强铝合金壁板构件为研究对象，开展时效成形复杂热/力条件下的蠕变/应力松弛行为及其确定的成形机理和同时伴生的强化相析出行为及其确定的成性机理的复杂制造过程研究，揭示强化相析出与蠕变/应力松弛行为的动态交互耦合作用机制，建立基于成形成性机理的时效成形过程宏微观耦合统一材料本构模型；研究复杂双曲率壁板构件在时效成形过程中的弹-粘塑性转变机制及其与回弹行为的关联规律，建立时效成形全过程多尺度仿真分析平台与高精度回弹预测方法，阐明热/力外场在时、空的不同匹配模式对析出相形核与长大、蠕变/应力松弛行为的影响规律，形成高强铝合金大型复杂构件多级热/力复合能场蠕变时效形性协同制造原理与工艺模型。

项目采用理论分析、实验研究与数值模拟相结合的方法，对高强铝合金蠕变时效成形过程非弹性形变和组织性能演变及调控进行了系统的研究。针对高强铝合金构件蠕变时效成形热力能场复杂、成形成性精确预测难的问题，构建了多台套拉/压蠕变/应力松弛试验系统，探明了三种典型航空用铝合金体系Al-Cu、Al-Cu-Mg和Al-Zn-Mg-Cu蠕变时效基本热力能场条件下的形/性演变机理与特征，建立了虑及形/性交互作用机理的蠕变时效宏微观统一本构模型的方法，开发了高强铝合金蠕变时效行为基础数据库和模型库；进一步探明了复杂热力能场条件下高强铝合金蠕变时效过程形/性演变机理，实现了构件尺度蠕变时效宏微观耦合统一本构表征；针对大型复杂构件蠕变时效高精度成形控制难的问题，提出了时效成形高精度回弹预测与动态加权回弹补偿方法，建立了时效成形全过程多场多尺度数字化分析平台，开发了模具型面优化设计软件系统，并通过两种典型航空构件时效成形试验，验证了方法的准确性；针对蠕变时效成形过程强化相析出状态调控、形/性协同制造难的问题，提出了预处理调控时效成形前初始组织与应力状态、电脉冲外场辅助蠕变时效形性协同演变等方法，有效扩大了时效成形的工艺窗口，找到了实现大型复杂构件蠕变时效形性协同制造的技术出路；项目形成了高强铝合金大型整体构件精确成形/成性协同制造理论与技术，支撑我国航空大型整体壁板构件制造水平与技术的跨越发展。. 项目执行期间，已发表和录用高水平期刊论文44篇（SCI论文31篇）；撰写国外专著1 章；申请中国发明和实用新型专利16项（已授权9项），获批软件著作权3项。研究团队获批科技部重点领域创新团队，黄明辉教授入选国家“万人计划”领军人才之科技创新人才，李恒教授入选国家“万人计划”中组部青年拔尖人才，并获得国家优秀青年科学基金资助；陆新江被评为教育部新世纪人才，共培养硕/博士生41人。项目部分研究成果成功应用于指导航空航天网格壁板类及复杂双曲类构件蠕变时效形性协同制造。