镍钛铌管连接件多工序组织遗传演变调控形状记忆效应机制

To break through the joining forming challenge with shape forming and property tailoring for "arterial-type" high pressure resistant ducts, a new idea, viz., excavating the shape memory effects (SME) via regulating the genetic evolution of shape memory alloy (SMA) microstructure, is proposed in tandem with the multi-pass characteristics of SMA joining process and the physical essence of the SME dependence on microstructure. To this end, this project is intended to research the advanced separable and shrinkable joining process of nickel-titanium-niobium (NiTiNb) SMA with wide hysteresis. Using the experimental study, microstructure characterization and macro-mesoscopic numerical simulation combining with crystal plasticity theory and solid phase transformation theory, the interplay mechanism between genetic evolution of microstructure and SME of the NiTiNb alloy under different initial microstructure conditions and various thermal-mechanical loadings will be revealed, then for predicting the genetic evolution of microstructure and deformation of tube joints during joining, an accurate and efficient micro-meso unified constitutive models of SMA as well as the thermal-mechanical coupling finite element (FE) models for all through joining process should be established, calibrated and numerical implemented. Based on the above models and using the experiments, the effects of the SMA material, joint geometry and processing parameters on the genetic evolution of microstructure and the joining quality with the high strength titanium alloy tubes will be thoroughly investigated and obtained. Finally, the new method for the integrated design of SMA material, tube joint geometry and processing parameters will be developed with the aim of improving the joining strength and sealing quality. The achievements should be of important scientific significance and application value in realizing the precision joining forming of duct components under high pressure extraordinary service conditions, excavating the application potential of advanced smart materials and enriching the precise plastic forming theory of high performance and light weight components.

针对“动脉血管类”耐高压管路形性一体化连接成形瓶颈，基于记忆合金连接多工序特点和形状记忆效应依赖微观组织的物理本质，本项目提出调控记忆合金组织遗传演变发掘其记忆效应的思路来解决上述难题。以宽滞后镍钛铌记忆合金可拆卸收缩式无扩口连接为对象，拟采用实验研究、组织性能表征、宏细观数值建模结合晶体塑性和固态相变理论，研究揭示记忆合金在不同初始状态和热力加载条件下的组织遗传演变与记忆效应关联机制;研究建立精确高效记忆合金宏细观统一本构模型和连接全过程热力耦合有限元模型;研究阐明材料、几何和工艺参数对高强钛合金管路可拆卸连接全过程组织遗传演变及连接质量的影响规律;以提高连接强度和密封性为目标，研究发展记忆合金管连接件材料-几何-工艺一体化设计新方法。本项目对于实现耐高压超常服役管路构件形性一体化连接成形制造、挖掘先进智能材料应用潜力和丰富航空航天高性能轻量化构件精确成形理论具有重要科学意义和应用价值。

针对“动脉血管类”耐高压管路形性一体化连接成形瓶颈，基于记忆合金连接多工序特点和形状记忆效应依赖微观组织的物理本质，提出了调控记忆合金组织遗传演变发掘其记忆效应的研究思路。基于此，采用实验研究、组织性能表征、数值建模结合固态相变理论，揭示了记忆合金热压缩变形下的形变机理和组织演变特征；阐明了等通道转角挤压大塑性变形晶粒细化对记忆合金记忆性能的影响机制；探明了记忆合金在不同热力加载路径下的组织遗传演变特征与形变机理，阐明了记忆合金微观组织演变与记忆效应的关联机制；建立了记忆合金本构模型和精确高效的连接成形全过程热力耦合有限元模型；探明了材料、几何和工艺参数对高强钛合金管路记忆合金式连接成形全过程组织遗传演变及连接质量的影响规律；以提高连接强度和密封性为目标，发展了记忆合金管连接件材料-几何-工艺一体化设计新方法，实现了管路构件记忆合金式高可靠性连接成形。本项目可为耐高压超常服役管路构件形性一体化连接成形制造和挖掘先进智能材料应用潜力提供理论和技术支撑。研究成果在本领域Int J Plast（IJP）、Int J Mech Sci（IJMS）、J Mater Process Technol（JMPT）、Chinese J Aeronaut（CJA）、J Alloys Compd（JAC）和Mater Sci Eng A（MSEA）等重要期刊发表学术论文25篇，SCI收录18篇；Elsevier出版社出版英文专著1部，英文书章1章；申请国家发明专利4项，获授权2项、公开2项；在重要学术会议做大会、主旨或邀请报告6次。