机械合金化法制备MCrAlY涂层的研究

发布时间：2018-04-27 15:55

本文选题：机械合金化 + MCrAlY　；参考：《南京航空航天大学》2010年硕士论文

【摘要】： 在机械合金化过程中,金属粉末在经历冷焊和细化的同时,其中一部分粉末会吸附在磨球表面及球磨罐的罐壁上,经过反复挤压和冷焊,形成一定厚度的涂层。根据这一原理,本文选取两种粉末体系NiCrAl·Y_2O_3和NiCrAlCo·Y_2O_3作为原始粉末,配以一定的球磨工艺参数,在管状碳钢材料内壁制备MCrAlY涂层,并有选择地对制得的合金层进行激光重熔。采用X射线衍射(XRD)、扫描电镜(SEM)、能谱仪(EDS)等对合金层进行显微组织、化学成分和相结构分析,并进行显微硬度测试、高温氧化实验、划痕实验来测试合金层性能。首先以NiCrAl·Y_2O_3为合金层原始粉末,在碳钢基体表面成功制得了NiCrAlY合金层。研究表明,球磨转速和球磨时间对合金层的形成都具有较大影响,在400 r/min球磨10h时获得合金层厚度最大(约35μm),此时合金层硬度最高且抗高温氧化性最好。在同样的工艺参数条件下,以NiCrAlCo·Y_2O_3作为合金层原始粉末获得的合金层的厚度有很大的提高。在400r/min球磨10h时形成的合金层厚度比NiCrAlY合金层大约15μm,且合金层的致密性、显微硬度、抗高温氧化性都得到了提高。选择400r/min球磨10h获得的合金层进行激光重熔,重熔后合金层的致密性得到提高,合金层-基体结合界面消失,合金层元素成分发生稀释,且显微硬度分布发生改变。本文还重点探讨了机械合金化技术制备合金层的机理和MCrAlY合金层的抗高温氧化机理。
[Abstract]:In the process of mechanical alloying, some of the metal powder will be adsorbed on the surface of the grinding ball and the tank wall of the ball mill tank during cold welding and refinement, and a certain thickness of coating will be formed after repeated extrusion and cold welding. According to this principle, two kinds of powder systems, NiCrAl Y_2O_3 and NiCrAlCo Y_2O_3, were selected as raw powder, and some parameters of ball milling were used to prepare MCrAlY coating on the inner wall of tubular carbon steel, and the alloy layer was selectively remelted by laser. The microstructure, chemical composition and phase structure of the alloy layer were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), SEM and EDS. The microhardness test, high temperature oxidation test and scratch test were carried out to test the properties of the alloy layer. Firstly, NiCrAl Y_2O_3 was used as the original powder of alloy layer, and the NiCrAlY alloy layer was successfully prepared on the surface of carbon steel substrate. The results show that the speed and time of ball milling have great influence on the formation of alloy layer. The thickness of alloy layer is the largest (about 35 渭 m) after 10 h ball-milling for 400 r/min. The hardness of alloy layer is the highest and the oxidation resistance at high temperature is the best. Under the same process parameters, the thickness of the alloy layer obtained by using NiCrAlCo Y_2O_3 as the original powder of the alloy layer is greatly improved. The thickness of the alloy layer formed after 10 hours of 400r/min milling is about 15 渭 m than that of the NiCrAlY alloy layer, and the densification, microhardness and high temperature oxidation resistance of the alloy layer are improved. After laser remelting of the alloy layer obtained by 400r/min ball milling for 10 h, the densification of the alloy layer was improved, the interface between the alloy layer and the matrix disappeared, the element composition of the alloy layer was diluted, and the microhardness distribution was changed. The mechanism of preparing alloy layer by mechanical alloying and the mechanism of high temperature oxidation resistance of MCrAlY alloy layer are also discussed in this paper.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TF123.111

【引证文献】