空间结构韧化钢基复合材料的冲击磨料磨损行为

Aim to improve the wear performance of ceramic particulates reinforced metal matrix composites under impact abrasion condition, the project is proposed to investigate the impact abrasion performance of the reinforcement architecture toughened MMCs which arose in recent decade, focuses the effect of the reinforcement architecture on the wear resistance of the composites. However, the reinforcement architecture including the shape, size and array in three-dimensional space can't be controlled very precisely and changed in a large scale with common fabrication techniques such as polymeric sponge impregnation process. It greatly define the research of the issue that the effect of the reinforcement architecture on the wear performance of the composites. In the project, A 3-dimension printer is applied to print the porous plastic pattern which would be used to fabricate the porous ceramic preform, further to fabricate MMCs by metal melt infiltration, just like the polymeric sponge in the polymeric sponge impregnation process. The method has the advantages of precise controlling and easy adjusting the architecture of the ceramic particles. The effect of the reinforcement architecture on the mechanical properties and compressive fatigue behavior will be researched. The abrasion wear, impact wear and impact abrasion wear will be studied step by step for the matrix metal, the ceramic particles uniformly reinforced MMCs and the reinforcement architecture toughened MMCs. The worn surface, the subsurface and the debris will be carefully characterized by advanced materials analysis techniques such as SEM, XRD, EDX and TEM, etc. and computer numerical calculation, especially the stress and strain distribution in the MMCs zone and matrix zone in the architecture, cracking of the ceramic particles and the origin and propagation of cracks in the MMCs zone, plastic deformation and hardening of the matrix zone. Through these work, the cooperation mechanism of the two zones at wear, the interaction between the abrasion and impact wear, the wear mechanism of the new wear resistant composites at impact abrasion, and the effect of the architecture on it would be all understood. The project will provide theory support for the optimal design of the reinforcement architecture toughened MMCs and improvement of the wear resistance, so is of great importance for the composites development and application to wider fields.

针对陶瓷颗粒增强钢铁基复合材料抗冲击磨料磨损性能不足的问题，研究空间结构韧化钢基MMCs的冲击磨料磨损行为，重点研究空间结构对其的影响。为此，在MMCs浸渍制备中，利用3D打印机制备陶瓷颗粒空间结构，实现结构单元形状、尺寸和排列的精确控制和大范围改变。研究空间结构对MMCs力学性能、压缩疲劳失效行为的影响。由简入繁逐步研究磨料磨损、冲击磨损和冲击磨料磨损行为，采用先进分析手段和计算机数值分析，对磨损表面、亚表层、磨屑等的形貌和组织特征进行深入表征，尤其是空间结构中复合材料区和纯基体区的应力应变分布、陶瓷颗粒的破碎和裂纹的萌生和扩展、塑性变形和加工硬化等行为。解决两种区域的磨损协同作用机理、冲击和磨料磨损的交互作用两个关键科学问题。最终掌握空间结构对钢基MMCs的磨损机理的影响规律，构建其冲击磨料磨损模型。项目为耐磨MMCs的结构优化设计和耐磨性提高提供理论依据。

本项目为了解决陶瓷颗粒增强钢铁基复合材料抗冲击磨料磨损性能不足的问题，研究空间结构韧化钢基复合材料的冲击磨料磨损行为。. 首先，项目采用3D打印和挤压铸造相结合的方法制备了陶瓷颗粒增强钢基复合材料以及纯钢三维互穿空间结构复合材料，优化了钢基体和粘接剂。. 其次，系统研究了空间结构形式和材料因素对复合材料力学性能的影响规律和破坏机理。获得了优化的空间结构-圆柱三维网络结构。所有复合区体积分数（35%~100%）的空间结构复合材料的压缩强度和塑性都高于均匀分散复合材料，体现出空间结构对复合材料优异的强化和韧化作用。降低复合区体积分数，提高基体强度，改善ZTA/40Cr钢界面结合，对三维结构相交处进行平滑处理，都可提高复合材料强度和塑性。. 在压缩疲劳下，空间结构复合材料的疲劳寿命约为均匀分散复合材料的6倍。X射线三维CT扫描表明，空间结构能够影响疲劳裂纹的萌生和扩展，阻止其向纵深扩展，从而提高疲劳寿命。. 然后，研究了三体磨料磨损条件下，空间结构复合材料的磨损性能及磨损机理。所有复合区体积分数复合材料的耐磨性都高于两种组成材料，尤其是50%时最高，比均匀分散复合材料提高40.8%。提高钢基体硬度，加入10%Ti粉，复合材料的耐磨性也升高。由此，建立了空间结构复合材料磨料磨损的数学模型。. 最后，系统研究了冲击磨料磨损条件下，空间结构复合材料耐磨性的变化规律及其磨损机理。同样，所有体积分数的空间结构复合材料的耐磨性都比均匀分散复合材料高，且在50%时达到最高，提高114.7%，证明三维互传网络结构能够大幅度提高复合材料的耐磨性。随基体硬度升高，复合材料耐磨性也显著提高。进一步调整复合区基体组织为高铬铸铁（基体区不变），复合材料耐磨性进一步提高19.9%。. 结合计算机模拟、纳米压痕等，总结出了空间结构复合材料的冲击磨料磨损机理，提出了空间结构对复合材料磨损的两方面贡献:复合区对周围基体区的保护，基体区对复合区裂纹的阻碍。项目为耐磨复合材料的结构优化和耐磨性提高提供了依据。