激光增材制造不同碳源颗粒增强Mn-Cu智能材料的阻尼机理和形状记忆行为

Mn-Cu smart alloys with high damping, super-elasticity and shape memory effect can be widely applied in the aerospace and medical fields. However, the application is limited due to the weaknesses including difficulty to process, high damping performance sensitive to temperature, low superelastic strain limit value and small recoverable strain of shape memory. In the project, selective laser melting (SLM) technology is applied to manufacture carbon-particle reinforced Mn-Cu matrix composites (Cp/Mn-Cu) with good mechanical properties, high damping and shape memory effect based on Mn powder, Cu powder and added carbon sources with different structures (carbon black, Carbon nanotubes and graphene). The effects of composition ratio, type of carbon source, process parameters and heat treatment on the solidification behavior, metallurgical defects, three-dimensional constrained phase transformation and interfacial behavior will be systematically investigated to explore the new damping mechanism and shape memory effect. Also, the regulation of component design, material preparation, process optimization, phase transition, mechanical properites, damping and shape memory effect will be realized by establishing the relationships between them. The results can enrich the non-equilibrium solidification theory of composites and open up a new way for rapid forming of high-performance smart materials.

Mn-Cu智能合金具有优良的阻尼、超弹性和形状记忆性能，在航空航天和医疗等领域极具应用前景。但加工难度大、阻尼性能对温度过于敏感、超弹性应变极限值低和形状记忆可恢复应变小的缺点限制了其应用。为此，本项目提出在Mn、Cu混合粉末中外加碳源（炭黑、碳纳米管和石墨烯），并采用激光选区熔化成形的新方法制备高致密度、优异力学性能、高阻尼和具有形状记忆效应的碳颗粒增强Mn-Cu基复合材料（Cp/Mn-Cu）。项目将系统研究成分配比、碳源种类、工艺参数对凝固结晶行为、冶金缺陷、三维约束下相变和界面反应的影响规律，探索Cp/Mn-Cu的新型阻尼机理和形状记忆行为，建立工艺参数-成分配比-力学/阻尼/形状记忆效应的关联，实现成分设计、材料制备、工艺优化、相变行为和力学/阻尼/形状记忆效应调控的有机融合。研究结果可丰富智能合金非平衡凝固理论，为快速成形高性能智能材料开辟新途径。

Mn‒Cu基SMAs因其较好的形状记忆性能、高阻尼系数、高弹性模量、宽且可调的转变温度范围、低生产成本和易于制造而被开发，在射频通信、传感器和执行器，能量采集器和生物医疗等领域具有广泛的应用前景。激光选区熔化（SLM）是一种典型的增材制造技术，可以有效解决高锰Mn‒Cu合金制造难题、扩大固溶解度极限、细化晶粒结构和促进亚稳定相形成。因此，本项目在Mn、Cu混合粉末中外加碳源（炭黑、碳纳米管和石墨烯），并采用SLM技术在较宽的工艺窗口下原位合成出系列碳颗粒增强Mn-Cu基复合材料（Cp/Mn-Cu）。项目探明了Mn、Cu和不同碳源的混合粉末在激光选区熔化成形的高频非稳态热循环下微熔池凝固结晶机理、三维约束型相变过程和界面行为；建立了材料成分配比-碳源类型-工艺参数-固态相变-阻尼和形状记忆行为的内在关联性；获得了制造兼具高致密、优异力学、高阻尼和形状记忆效应的Cp/Mn‒Cu材料的成分设计和工艺制造方法。在本项目资助下，研究团队发表SCI论文9篇，会议论文4篇，申请专利4项，参加学术会议4次，培养研究生7名。