多陶瓷相强化Fe基纳米复合材料的激光选区熔化原位合成机理研究

项目名称： 多陶瓷相强化Fe基纳米复合材料的激光选区熔化原位合成机理研究

项目编号： No.51505166

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 机械、仪表工业

项目作者： 宋波

作者单位： 华中科技大学

项目金额： 20万元

中文摘要： 金属基纳米复合材料具有高强度与高刚度且比重小，被广泛应用于机械、汽车、航天航空等领域。传统热加工制备金属基纳米复合材料存在晶粒长大、纳米颗粒易团聚等问题，且加工与成形复杂结构的金属基纳米复合材料仍存在较高的难度。本项目选取Fe/(Cr3C2, WC, Mo2C)材料体系，创新性地提出通过激光选区熔化(SLM)技术直接从金属和陶瓷机械混合粉末原位合成多相强化Fe基纳米复合材料。通过可控的SLM能量输入实现陶瓷的部分熔化与Fe发生固溶反应以期改善Fe基性能，残留的陶瓷纳米颗粒作为弥散强化相，建立固溶和弥散硬质相共存的调控机制。充分利用SLM过程高冷却速率以及微熔池凝固成形特性，拟解决传统热加工中晶粒长大、纳米颗粒团聚等科学问题。通过对成形件的微观结构与力学性能的综合分析，建立材料体系、SLM成形工艺和成形件微结构性能之间的关系模型，为实现复杂结构高性能Fe基纳米复合材料低成本成形提供理论支持。

中文关键词： 激光选区熔化；激光成形；金属基复合材料；陶瓷强化；原位合成

英文摘要： Metal matrix nanocomposites with high strength and high stiffness as well as small specific weight, are widely used in machanical, automotive, aerospace and other fields. Metal matrix nanocomposites prepared by traditional thermal processing have some problems of grain growth and nanoparticle agglomeration. Moreover, it is difficult to machine or form complex nanocomposite parts by traditional methods. In this project, Fe/(Cr3C2, WC, Mo2C) material system will be used to prepare nanocomposites reinforced by multiphases. Selective Laser melting (SLM) technology is innovatively proposed to in-situ synthesize nanocomposites directly from metal and ceramic mechanically-mixed powders. The partial melting of ceramics could be achieved by controlling SLM energy input and the remaining ceramic nanoparticles could be considered as a dispersion of strengthening phase. Fe-based nanocomposites with excellent performance would be obtained with the solid solution and dispersion strengthening. The high cooling rate and micro-molten pool solidification characteristics during SLM process are expected to solve the grain growth, nanoparticle agglomeration and other scientific issues during traditional thermal processing. The relationship between the composite material system, SLM forming processing and the parts’ performance could be established by a comprehensive analysis of microstructure and mechanical properties of Fe-Cr3C2-WC-Mo2C parts. This project would provide theoretical support for low-cost forming of Fe nanocomposites with complex structure and high-performance.

英文关键词： Selective laser melting;Laser forming;Metal matrix composites;Ceramic reinforcement;In-situ synthesis