脉冲电流辅助铍热塑性变形过程中的电热效应研究

The low density, high melting point, high specific strength, specific stiffness and excellent nuclear properties of beryllium make it a strategic material for national security. It is not only the preferred material for space reactors but also the ideal structural material for aerospace applications. At present, China mainly uses the powder metallurgy and machining to manufacture metal beryllium parts, and the shortcomings of high cost and low efficiency make it unable to meet batch production demand. Though the hotforming adopted abroad can realize the plastic forming of metal Beryllium, the problems of coarse structure, low forming limit and cracks affect the mechanical properties of the formed parts and are difficult to meet the dual requirements of "shaper controlling" and "performance controlling", resulting in a bottleneck to be solved. The novel idea of this program lies in proposing the current assisted Beryllium hot plastic forming technology, Accordingly, the deformation mechanism of the material under the combined effect of electric, thermal and force is highly emphasized in the research. Both macroscopic and microscopic action mechanisms of pulse current will be determined. Meanwhile, the hot plastic defromation properties under pulse current and the electro-induced multiple effects of Beryllium will be revealed. The characteristics of forging deformation properties under coordinated loading will be investigated and the combined effect of pulse current and loading on the microstructure evolution of materials will also be revealed, the problem of shape controlling and performance controlling of Beryllium hot plastic forming will be solved.

金属铍低密度、高熔点、高比强度、比刚度及优异的核性能等特性使其成为一种关系国家安全的基础战略材料，不仅是空间反应堆的首选材料，也是航空航天领域理想的结构材料。目前我国主要采用粉末冶金与机械加工结合的方式制造金属铍零件，高成本、低效率的缺点使其无法满足批产需求。国外采用的热成形虽然可以实现金属铍的塑性成形，但组织粗大、成形极限低及裂纹等问题，影响成形构件的力学性能，难以满足“控形”和“控性”的双重需求，这一瓶颈问题有待解决。本项目首次提出脉冲电流辅助金属铍热塑性成形技术，电、热、力三场综合作用下材料的变形机制是研究的重点，脉冲电流作用下材料的宏微观变形机制是需明确的科学问题。本项目的研究将揭示金属铍在脉冲电流作用下的热塑性变形特性及电致多重效应，解明协调加载下锻造流动特性，揭示脉冲电流及载荷对材料微观组织演变的综合作用，掌握协调控制方法，解决金属铍热塑性成形的控形控性问题。

金属铍低密度、高熔点、高比强度、比刚度及优异的核性能等特性使其成为一种关系国家 安全的基础战略材料，不仅是空间反应堆的首选材料，也是航空航天领域理想的结构材料。目前我国主要采用粉末冶金与机械加工结合的方式制造金属铍零件，高成本、低效率的缺点使其无法满足批产需求。国外采用的热成形虽然可以实现金属铍的塑性成形，但组织粗大、成形极限低及裂纹等问题，影响成形构件的力学性能，难以满足“控形”和“控性”的双重需求，这一瓶颈问题有待解决。本项目首次提出脉冲电流辅助金属铍热塑性成形技术，电、热、力三场综合作用下材料的变形机制是研究的重点，脉冲电流作用下材料的宏微观变形机制是需明确的科学问题。本项目的研究将揭示金属铍在脉冲电流作用下的热塑性变形特性及电致多重效应，解明协调加载下锻造流动特性，揭示脉冲电流及载荷对材料微观组织演变的综合作用，掌握协调控制方法，解决金属铍热塑性成形的控形控性问题。