【作者】 李兵；

【导师】 陈维平；

【作者基本信息】 华南理工大学 ， 材料加工工程， 2020， 硕士

【摘要】 高温铝液具有很强的腐蚀性,在铝合金熔炼、热浸镀铝及铝合金产品制造过程中,模具、坩埚等与铝液直接接触的零部件在工作中会受到铝液的腐蚀与冲刷、磨损的交互作用,极易损坏。这将造成铝液污染、制品质量下降、生产成本提高、效率降低等问题。因此开发新型耐铝液腐蚀-磨损材料是当前工业生产中的迫切需求。Fe-Cr-B合金是一种非常有潜力的耐铝液腐蚀-磨损材料,合金中的硼化物具有优异的耐铝液腐蚀-磨损性能,但硼化物的网状分布严重割裂了基体,造成材料的韧性较差,很难应用到实际生产。稀土变质处理及合金化可以改善硼化物的形态,但关于变质处理与合金化对Fe-Cr-B合金耐铝液腐蚀-磨损性能的影响鲜有报道。本文以Fe-Cr-B合金为研究对象,通过添加和调整合金中Ce、W、B元素的含量,研究了上述元素对Fe-Cr-B合金组织、力学性能、耐铝液腐蚀及腐蚀-磨损性能的影响。主要研究结论如下:（1）Fe-Cr-B合金通过稀土Ce变质处理配合W合金化的方式,可获得良好的冲击韧性,M5（Fe-15.0Cr-1.4B-1.0W-0.6Ce）的冲击韧性比M1（Fe-15.0Cr-1.3B）提高了2.9倍。Ce的加入可以脱硫脱氧,净化晶界,而W则可以提高硼化物的韧性,且二者共同作用,可使合金中硼化物连续性逐渐降低、尺寸减小,硼化物的分布更加均匀,进而提高合金的冲击韧性。另外,随着W、B含量的升高,材料的洛氏硬度与压缩强度逐渐提高,但材料的塑性逐渐减小。（2）M₂B型硼化物具有优异的耐铝液腐蚀性能,且硼化物的体积、形态及分布均会对材料的耐铝液腐蚀性能产生影响。合金M10（Fe-15.0Cr-3.9B-4.9W-0.6Ce）的耐铝液腐蚀性能最佳,约为H13钢的5.3倍。B含量的升高,可以提高合金中硼化物的体积分数,并形成更大尺寸的硼化物来阻挡铝液的腐蚀,延缓金属间化合物层的剥落,进而提高材料的耐铝液腐蚀性能。合金M5耐铝液腐蚀与韧性的综合性能最佳,Ce和W的添加使硼化物在基体中的分布更加均匀,提高韧性的同时还可以延缓铝液的侵蚀从而保护基体。（3）不同成分的Fe-Cr-B合金均具有优异的耐铝液腐蚀-磨损性能。M10（Fe-15.0Cr-3.9B-4.9W-0.6Ce）的耐腐蚀-磨损性能最佳,比H13提高了2.9倍。M5（Fe-15.0Cr-1.4B-1.0W-0.6Ce）兼具韧性、耐铝液腐蚀及腐蚀-磨损性能,综合性能优异。合金在铝液中的腐蚀-磨损材料流失量远大于其纯腐蚀与纯磨损条件下材料流失量之和,即腐蚀与磨损具有相互促进的效果,二者的交互作用是导致Fe-Cr-B合金失效的主要原因。更多还原

【Abstract】 Molten aluminum is very corrosive.During the process of aluminum alloy smelting,hot-dip aluminum plating and aluminum alloy products,parts such as molds,crucibles,etc.that are in direct contact with the molten aluminum will be subject to the interaction of corrosion and wear of molten aluminum and are easily damaged.This will cause problems such as aluminum liquid pollution,product quality decline,production cost increase,and efficiency decrease.Therefore,the development of a new type of corrosion-wear resistant materials in molten aluminum is an urgent need.Fe-Cr-B alloy is a very promising material for corrosion-wear of molten aluminum.The boride in the alloy has excellent resistance to corrosion-wear resistance of liquid aluminum.The toughness of the material is poor,making it difficult to apply to actual production.However the network distribution of boride cuts the matrix,resulting in poor toughness of the material,so it is difficult to apply to actual production.Rare earth modification and alloying can improve the morphology of boride,but there are few reports about the effect of modification and alloying on the corrosion-wear resistance of Fe-Cr-B alloy.This paper takes Fe-Cr-B alloy as the research object,by adding and adjusting the content of Ce,W and B elements,the structure,mechanical properties,resistance to molten aluminum corrosion and corrosion-wear of the above elements on Fe-Cr-B alloy are studied.The main research conclusions are as follows:（1）Fe-Cr-B alloy can achieve good impact toughness through Ce modification and a small amount of W addition.The impact toughness of M5（Fe-15.0Cr-1.4B-1.0W-0.6Ce）is 2.9times higher than that of M1（Fe-15.0Cr-1.3 B）.The addition of Ce can desulfurize and deoxidize and purify the grain boundaries,while W can improve the toughness of the boride,and the combination of the two can gradually reduce the continuity and size of the boride in the alloy,and the distribution of boride is more uniform Improve the impact toughness of the alloy.In addition,The rockwell hardness and compressive strength of the material increases with the increase of W and B content,but the plasticity gradually decreases.（2）M₂B boride has excellent corrosion resistance to molten aluminum,and the volume,shape and distribution of boride will affect the corrosion resistance of molten aluminum.M10（Fe-15.0Cr-3.9B-4.9W-0.6Ce）has the best corrosion resistance to molten aluminum,about 5.3times that of H13 steel.The increase of B content can increase the volume fraction of boride in the alloy,and form a larger size of boride to block the corrosion of the molten aluminum,delay the peeling of the IMC,and then improve the corrosion resistance of the material to molten aluminum.M5 has the best comprehensive performance of toughness and corrosion resistance of molten aluminum.The addition of Ce and W makes the distribution of boride in the matrix more uniform.While improving toughness,it can also delay the corrosion of molten aluminum and protect the matrix.（3）Fe-Cr-B alloys with different compositions all have excellent resistance to corrosion-wear of molten aluminum.M10 has the best corrosion-wear resistance to molten aluminum,about 2.9 times higher than that of H13.M5 has the best comprehensive performance of toughness and corrosion-wear resistance of molten aluminum.The corrosion-wear loss of the alloys in molten aluminum is much higher than the sum of its weight loss under pure corrosion and pure wear,In the corrosion-wear process of materials,corrosion and wear have a mutually promoting effect,and the interaction between corrosion and wear is the main reason for the failure of Fe-Cr-B alloy.更多还原