预沉淀相在时效成形过程的遗传效应研究

Age forming is a precise forming technology combing with both creep forming and stress aging technology. It is advantageous in the manufacture of larger complex integral wing-skin panel. The pre-precipitation phase formed by pre-aging will improve or degrade the final performance, the phenomenon of which is termed as transferring effect. The effort done to obtain desirable pre-precipitation phase by pre-aging and wanted transferring effect thereafter will make the microstructure processable improving the performance of the workpieces, rasie the the creep resistance at early stage of age forming, and minish the creep resistance difference and anisotropy over the whole age forming process, all of which are beneficial to the precise forming. This project combines the study of static precipitation, creep forming, dynamic precipitation with advanced computational method to tudy the microstructure evolution over the whole range from pre-ageing to age froming for the aluminum alloy of 2000 series and 7000 series.The microscopic phase field method is employed to simulate the evolutional-microstructure over the whole range from pre-ageing to age froming, while the experiment of pre-aging and the subsequent age forming, micro-analysis, and performance testing are done to verify the computation results. According to the relationship of pre-aging process- - pre-precipitation phase- - transferring effect- - equilibrium precipitation phase - - mechanical performance - - processing property, the transferring effect determined by precipitation stablility, dispersity, arranement and strucuture are illustrated in detail. The scientific study, which is extracted from the background of structural control, performance controll and shape controll, will provide theoretical support for the integrated design of pre-ageing and age forming.

时效成形是蠕变成形与应力时效相结合的精确成形技术，用于制造铝合金大型复杂整体壁板等构件有显著技术优势。预时效处理获得的预沉淀相对随后时效成形过程形成沉淀相有重要影响，称为遗传效应。合理控制预沉淀相及其遗传效应，可改善时效成形构件的微观组织，优化性能；同时，减小时效成形工艺全过程的蠕变抗力差异和各向异性，益于精确成形。 本项目将静态沉淀、蠕变成形、动态沉淀、先进模拟方法的研究相结合，以2000和7000系铝合金为对象，采用微观相场方法模拟预时效至时效成形全过程的微观结构演化，结合预时效与时效成形工艺实验、微观分析、性能测试，围绕预时效- - 预沉淀相- - 时效成形- - 沉淀相- - 遗传效应- - 力学性能- - 工艺性能的关系，研究预沉淀相稳定程度、取向、结构等决定的遗传效应，是从时效成形工艺的控构、控性、控形的应用背景中，凝练出的科学问题，可为预时效与时效成形工艺的一体化设计，提供理论支撑。

时效成形是蠕变成形与应力时效相结合的精确成形技术，用于制造铝合金大型复杂整体壁板等构件有显著技术优势。预时效处理获得的预沉淀相对随后时效成形过程形成沉淀相有重要影响，称为遗传效应。合理控制预沉淀相及其遗传效应，可改善时效成形构件的微观组织，优化性能；同时，减小时效成形工艺全过程的蠕变抗力差异和各向异性，益于精确成形。.本项目将静态沉淀、蠕变成形、动态沉淀、先进模拟方法的研究相结合，以2000和7000系铝合金为对象，采用微观相场方法模拟预时效至时效成形全过程的微观结构演化，结合预时效与时效成形工艺实验、微观分析、性能测试，围绕预时效——预沉淀相——时效成形——沉淀相——遗传效应——力学性能——工艺性能的关系，研究预沉淀相稳定程度、取向、结构等决定的遗传效应，是从时效成形工艺的控构、控性、控形的应用背景中，凝练出的科学问题，可为预时效与时效成形工艺的一体化设计，提供理论支撑。.通过本项目的研究工作探明了沉淀强化型合金中的预沉淀相/沉淀相及相界面的热力学稳定性、力学性质，揭示了预沉淀相/沉淀相稳定程度、取向、结构的要素对时效成形组织遗传性的影响规律，提出优化预沉淀相、时效成形沉淀相的科学原则。.有22篇论文在《Journal of Alloys and compounds》、《Computational materials science》、《Chinese physics B》、《Phys. Status solid B》等国内外重要刊物发表，全部被SCI收录，影响因子大于2的论文5篇，申请专利2项，获得陕西省科学技术二等奖一项，培养青年教师1人，研究生12名。超额完成预期目标。