钛合金表面微弧氧化强流脉冲电子束复合处理技术

发布时间：2018-05-15 04:22

本文选题：微弧氧化 + 强流脉冲电子束　；参考：《沈阳理工大学》2017年硕士论文

【摘要】：本文采用微弧氧化、强流脉冲电子束复合处理的方法,在TC4合金表面制备新型硬质金属陶瓷复合处理层。在其余情况相同条件下,采用不同微弧氧化电解液配方,或在不同微弧氧化正向电压、氧化时间下制备复合改性金属陶瓷层。依据检测结果,研究确定预制微弧氧化层工艺对复合处理层影响,选择微弧氧化工艺参数。本文分别对单一改性处理的微弧氧化层、脉冲电子束改性层及复合处理的复合涂层,进行硬度、耐磨性、耐蚀性等性能方面测试。对比分析不同改性方法对膜层性能的影响,并讨论形成原因。观察复合处理层形成过程,分析归纳改性层表面形貌、组织结构及其性能的变化规律,结合影响因素及复合处理层的性能改变,初步阐述钛合金表面微弧氧化脉冲强流电子束复合处理层形成机理。研究表明,采用不同微弧氧化电解液配方,经强流脉冲电子束处理,均可获得复合表面平滑光亮的复合改性涂层,相较而言,采用Na2SiO3-(NaPO3)6-NaAlO2微弧氧化电解液配方,制备的复合处理层表面质量更高。微弧氧化正向电压及氧化时间均为复合处理层的影响因素。氧化正向电压是复合涂层组织含量的主要影响因素,正向电压最佳工艺参数为500V。氧化时间是复合层表面质量的主要影响因素,氧化时间的最佳工艺参数为5min。从从性能方面上来看,复合处理层从各方面均较单一改性层有更良好的性能。复合处理层中不仅含有微弧氧化的硬质氧化陶瓷相作为增强相,同时脉冲电子束的重熔作用可降低改性层表面缺陷、细化了晶粒,使其硬度得到进一步提高,复合处理层的硬度约为基体的4倍、微弧氧化层的2倍。复合层改性层耐磨性也得到显著提高,耐磨系数仅为0.19,磨损量为0.0009g。与此同时,复合处理层的耐酸碱盐的腐蚀能力也得到不同程度的改善。从形成机理上来看,微弧氧化层到复合处理层过程中,表面火山丘状组织消失,变为平滑组织;改性层表面高温稳定相增多。实验发现,复合层表面有纹理状组织和熔坑等缺陷,其中熔坑可消除,纹理状组织无法消失。
[Abstract]:In this paper, a new hard cermet composite layer was prepared on the surface of TC4 alloy by means of micro-arc oxidation and high current pulsed electron beam composite treatment. Under the same conditions, the composite modified cermet coatings were prepared by using different microarc oxidation electrolyte formulations, or under different forward voltages and oxidation time of microarc oxidation. Based on the test results, the influence of prefabricated microarc oxidation process on the composite layer was studied and the parameters of microarc oxidation process were selected. In this paper, the hardness, wear resistance and corrosion resistance of single modified micro-arc oxidation layer, pulsed electron beam modified layer and composite coating were tested. The effects of different modification methods on the properties of the film were analyzed, and the formation reasons were discussed. The formation process of the composite treatment layer was observed, and the surface morphology, microstructure and properties of the modified layer were analyzed and summarized, and the influence factors and the performance changes of the composite treatment layer were combined. The formation mechanism of pulsed high current electron beam composite treatment layer on titanium alloy surface by micro arc oxidation is described. The results show that the composite coating with smooth and bright surface can be obtained by using different microarc oxidation electrolyte formulations and high current pulsed electron beam treatment. Compared with Na2SiO3-(NaPO3)6-NaAlO2 microarc oxidation electrolyte formulation, The surface quality of the prepared composite layer is higher. The forward voltage and oxidation time of microarc oxidation are the influencing factors of the composite treatment layer. The oxidation forward voltage is the main influence factor of the structure content of the composite coating, and the optimum process parameter of the forward voltage is 500V. The oxidation time is the main factor affecting the surface quality of the composite layer, and the optimum process parameter of the oxidation time is 5 min. From the aspect of performance, the composite treatment layer has better performance than the single modified layer in all aspects. The composite layer not only contains the hard oxidized ceramic phase of micro-arc oxidation as reinforcement phase, but also can reduce the surface defects of the modified layer by pulsed electron beam remelting, refine the grain size and further improve the hardness of the modified layer. The hardness of the composite layer is about 4 times of that of the substrate and 2 times of that of the micro-arc oxidation layer. The wear resistance of the modified composite layer was also improved remarkably, the wear resistance coefficient was only 0.19, and the wear amount was 0.0009g. At the same time, the corrosion resistance of the composite layer was improved to some extent. From the mechanism of formation, the surface fire mound structure disappeared from the micro-arc oxidation layer to the composite treatment layer, and the surface of the modified layer became smooth and stable at high temperature. It is found that there are some defects in the surface of the composite layer, such as texture structure and melting pit, which can be eliminated, but the texture structure can not disappear.
【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG178

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