新型Fe-Cr-B铸钢及其三维网络结构ZrO_2增强复合材料的铝液腐蚀—磨损研究

发布时间：2018-03-16 20:36

本文选题：铝液　切入点：腐蚀-磨损　出处：《华南理工大学》2015年博士论文　论文类型：学位论文

【摘要】：在熔铝铸造、热浸镀铝及铝合金复合材料制造等行业,铝液腐蚀-磨损通常会造成坩埚和铸模等重要零部件失效,因此,研制出优异耐铝液腐蚀-磨损性能的铁合金新材料具有重要的意义。本文以在钢基体中生成Fe2B相为设计目标,采取以B元素为主,以Cr、Mo等元素为辅的合金化方式,在中频感应电炉中制备出新型Fe-Cr-B铸钢,并研究了Cr、B含量对Fe-Cr-B铸钢铝液腐蚀及腐蚀-磨损性能的影响。在此基础上,对多孔ZrO2陶瓷骨架表面镀镍,并利用砂型铸造制备出三维网络结构ZrO2/Fe-Cr-B铸钢复合材料,同时研究了其耐铝液腐蚀-磨损性能。主要结论如下:(1)Fe-Cr-B铸钢具有优异的耐铝液腐蚀性能,其中Fe-12.3 wt.%Cr-5.88wt.%Mn-3.6 wt.%B-1.89 wt.%Mo(M6)的耐铝液腐蚀性能比H13提高了5倍。M2B(M=Fe,Cr,Mo)型硼化物对提高Fe-Cr-B铸钢的耐铝液腐蚀性能起到重要作用:在铝液腐蚀过程中,M2B型硼化物比Fe基体具有更低的的铝液腐蚀速率,它们明显提高了铸钢的耐铝液腐蚀性能;其中富Cr的Fe2B型硼化物,与铝液反应生成两相相间的层片结构;而富Mo的Fe2B型硼化物则发生断裂;二者失效后都镶嵌在Cr合金化的Fe-Al金属间化合物层中,起到“树根”效应,能抑制金属间化合物层的剥落。(2)Fe-Cr-B铸钢具有优异的耐铝液腐蚀-磨损性能,其中M6的耐铝液腐蚀-磨损性能比H13提高了3倍。初生富Cr的Fe2B型硼化物对提高Fe-Cr-B铸钢的铝液腐蚀-磨损性能起到重要作用:在铝液腐蚀-磨损过程中,初生富Cr的Fe2B型硼化物表现出比基体更慢的铝液腐蚀-磨损速率,进而凸出基体表面并承受主要的载荷,导致摩擦副之间的铝液膜非常薄,从而使铝液腐蚀不充分,引起初生富Cr的Fe2B型硼化物中的Fe元素发生优先溶解并形成Cr含量很高的金属间化合物,其主要组成元素为Cr、Al和B,但这种金属间化合物最终会发生断裂而失效。(3)采用砂型铸造能够制备出界面结合良好的三维网络结构ZrO2/Fe-Cr-B铸钢复合材料,这种复合材料的耐铝液腐蚀-磨损性能比H13提高了近10倍;ZrO2对提高复合材料的耐铝液腐蚀-磨损性能起到重要作用:在铝液腐蚀-磨损过程中,ZrO2陶瓷承受主要的载荷,金属基体则主要经受动态铝液的腐蚀。(4)对于Fe-Cr-B铸钢及H13而言,铝液腐蚀-磨损引起的失重要远远大于同等实验参数下单一的铝液腐蚀及干摩擦磨损引起的失重之和,它们在铝液腐蚀-磨损过程中的交互作用率在0.8以上,表明铝液腐蚀与磨损之间的交互作用是这两种材料在铝液腐蚀-磨损环境中失效的最主要原因。
[Abstract]:In industries such as molten aluminum casting, hot-dip aluminizing and aluminum alloy composite material manufacturing, corrosion wear of molten aluminum usually results in the failure of important parts such as crucible and mould. It is of great significance to develop a new ferroalloy material with excellent corrosion resistance and wear resistance of molten aluminum. In this paper, the formation of Fe2B phase in steel substrate is taken as the design goal, and the alloying method is adopted, which is based on element B and supplemented by elements such as Cr-Mo and so on. A new type of Fe-Cr-B cast steel was prepared in an intermediate frequency induction furnace. The effect of CrB content on the corrosion and corrosion-wear properties of Fe-Cr-B cast steel was studied. On this basis, nickel plating on the porous ZrO2 ceramic framework was carried out. Three-dimensional network ZrO2/Fe-Cr-B cast steel composites were prepared by sand mold casting, and the corrosion and wear resistance of the composites were studied. The main conclusions are as follows: 1) Fe-Cr-B cast steel has excellent corrosion resistance to molten aluminum. The corrosion resistance of Fe-12.3 wt.%Cr-5.88wt.%Mn-3.6 wt.%B-1.89 wt.MoM6) is 5 times higher than that of H13. The boride type plays an important role in improving the corrosion resistance of Fe-Cr-B cast steel. In the process of molten aluminum corrosion, M2B type boride has a lower corrosion rate than Fe matrix. They obviously improve the corrosion resistance of cast steel, in which Cr rich Fe2B boride reacts with molten aluminum to form a lamellar structure of two phases, while Mo rich Fe2B boride breaks. Both of them are embedded in Cr alloyed Fe-Al intermetallic compound layer after failure, which plays a "tree root" effect and can inhibit the spalling of intermetallic compound layer. Fe-Cr-B cast steel has excellent corrosion and wear resistance to aluminum liquid. The corrosion and wear resistance of M6 is three times higher than that of H13. The primary Cr rich Fe2B boride plays an important role in improving the corrosion and wear properties of Fe-Cr-B cast steel. The primary Cr rich Fe2B boride exhibits a slower corrosion wear rate than the matrix, and then protrudes the substrate surface and bears the main load, which leads to the thin aluminum film between the friction pairs, which makes the molten aluminum corrosion insufficient. The Fe element in the primary Cr rich Fe2B boride dissolves preferentially and forms the intermetallic compound with high Cr content. The main elements are Cr-Al and B, but this intermetallic compound will eventually fracture and fail. 3) Sand mold casting can be used to fabricate 3D network ZrO2/Fe-Cr-B cast steel composites with good interfacial bonding. The corrosion and wear resistance of the composite is 10 times higher than that of H13, which plays an important role in improving the corrosion and wear resistance of the composite: in the process of corrosion and wear of molten aluminum, ZrO2 ceramics bear the main load. For Fe-Cr-B cast steel and H13, the weight loss caused by corrosion wear of molten aluminum is much larger than that caused by corrosion and dry friction wear under the same experimental parameters. The interaction rate of these two materials in the process of corrosion and wear of molten aluminum is more than 0.8, which indicates that the interaction between corrosion and wear of molten aluminum is the main reason for the failure of these two kinds of materials in the corrosion wear environment of molten aluminum.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TG142;TB333

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