等离子堆焊反应合成陶瓷增强金属基复合材料改性层

发布时间：2018-01-04 10:20

本文关键词：等离子堆焊反应合成陶瓷增强金属基复合材料改性层　出处：《沈阳工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：磨损是造成材料失效的一个重要原因，许多机械零件长期在苛刻的工作环境下服役，表面承受较高的冲击载荷，常常因为磨损而报废，不但降低了其使用寿命，还会造成巨大的经济损失和资源浪费。材料表面改性技术可以改变材料表面的显微组织、成分和相结构，以达到提高材料表面耐磨性能的目的。颗粒增强金属基复合材料兼具金属材料和陶瓷材料的优良性能特点，，传统外加颗粒增强相制备金属基复合材料常存在增强粒子与基体界面润湿性差、增强相分布不均匀等问题，使材料性能达不到预期效果，原位合成法则克服了这一难题，通过这种方法制备的金属基复合材料热力学稳定性好，增强相在基体中分散均匀，界面结合良好，有效改善材料表面性能，具有很大的应用前景。本课题采用等离子堆焊工艺在304L不锈钢表面原位合成WC增强Ni基合金复合材料改性层，对堆焊工艺参数及性能进行了优化。采用金相显微镜、扫描电子显微镜、能谱仪、X射线衍射仪、显微硬度计及销-盘磨损试验机等仪器设备分别对改性层的显微组织、成分、相结构、硬度及摩擦磨损性能进行分析和测试。同时，在改性层中添加适量的稀土氧化物，研究稀土元素对改性层性能的影响。试验结果表明，制备外加WC颗粒增强Ni基合金复合材料改性层时，WC颗粒出现“沉底”现象，改性层组织不均匀，原位合成WC增强Ni基合金复合材料改性层中，WC呈块状，弥散分布于整个改性层。外加WC颗粒制备的Ni基复合材料改性层的显微硬度呈梯度分布，底部WC聚集区显微硬度明显高于改性层中上部，改性层平均显微硬度为925HV，改性层的磨损机制主要为疲劳断裂和粘着磨损，相对耐磨性为12.0；原位合成WC增强Ni基合金改性层显微硬度分布较均匀，平均显微硬度最高可达915HV，改性层磨损面呈犁沟状，磨损机制主要为磨料磨损，相对耐磨性显著提高。添加稀土氧化物以后，改性层组织变得细小致密，WC颗粒的形态、尺寸和分布均发生了变化，各改性层显微硬度均有不同程度的提高，相对耐磨性最高可达36.0。
[Abstract]:The material surface modification technology can change the microstructure , composition and phase structure of the surface of the material so as to achieve the purpose of improving the wear resistance of the material . The microstructure , composition , phase structure , hardness and friction and wear properties of the modified layer were analyzed and tested by using the plasma surfacing technique on 304L stainless steel surface . The microstructure , composition , phase structure , hardness and friction and wear properties of the modified layer were analyzed and tested by using metalloscope , scanning electron microscope , energy dispersive spectrometer , X - ray diffraction instrument , microhardness tester and pin - disc wear testing machine . The results show that when the modified layer of WC particle reinforced Ni - base alloy composite material is prepared , WC particles appear as " bottom " phenomenon , and the microstructure of the modified layer is not uniform . In situ synthesis of WC - reinforced Ni - base alloy composite material , the microhardness of the modified layer is higher than that in the modified layer . The average microhardness of the modified layer is higher than that of the modified layer . The wear mechanism of the modified layer is higher than that of the modified layer . The wear mechanism of the modified layer is obviously higher than that of the modified layer . The microstructure of the modified layer is very fine and dense . The microhardness of the modified layer is improved , and the relative wear resistance is up to 36.0 .

【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB333

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