Mn和Ce对Fe-Ni-Mn-C-Si-Ce系合金组织和性能的影响

采用熔炼法制备出新型高耐磨的Fe-20Ni-xMn-3.5C-2.5Si系固体自润滑材料,研究稀土元素Ce对Fe-20Ni-xMn-3.5C-2.5Si系合金中石墨的球化作用及Mn含量对力学性能及摩擦磨损性能的影响。结果表明：随着Mn含量的增加,合金凝固组织中奥氏体的硬度逐渐增大,特别是Fe-20Ni-xMn-3.5C-2.5Si-0.75Ce系合金在摩擦过程中的表面硬度大幅度提高,呈现出高锰钢特有的表面加工硬化性质,通过TEM可以观察到磨损表面生成孪晶型马氏体;添加0.75%（质量分数）的稀土Ce可以使结晶的石墨球化,使抗拉强度和抗弯强度大幅度提高,大约比未经球化处理的提高3～5.8倍;稀土Ce的加入可以促进Fe1.1Mn3.9C2型碳化物的生成,使材料的耐磨性进一步提高,其中Fe-20Ni-16Mn-3.5C-2.5Si-0.75Ce合金的磨损率最低,大约是QT500球墨铸铁的1/13。

Effects of Mn and Ce additions on structures and properties of Fe-Ni-Mn-C-Si-Ce alloys

Fe-20Ni-xMn-3.5C-2.5Si solid self-lubricating materials with property of high-wearing were prepared by melting method.The spheroidization effect of rare earth Ce on graphite and the effect of Mn addition on mechanical properties and tribological performances of Fe-20Ni-xMn-3.5C-2.5Si alloys were studied.The results show that the austenite hardness of solidifying structures increases as the manganese content increases.The surface hardness of Fe-20Ni-xMn-3.5C-2.5Si-0.75Ce alloy increases widely after being worn and it appears the work-hardening of surface as like the high manganese-containing steel.The type of compound twin martensite on surface can be observed by TEM.The spheroidization effect of 0.75%(in mass fraction)of rare earth cerium on the graphite during crystallization is effective.The spheroidized alloy has higher tensile strength and flexural strength which is about 3?5.8 times higher than those of the non-spheroidized alloy.With the addition of rare earth Ce,the second phase Fe1.1Mn3.9C2,which makes the wear resisting property further increase,appears in matrix.Fe-20Ni-12Mn-3.5C-2.5Si-0.75Ce alloy has the lowest wear rate which is about 13 times lower than that of the spheroidal cast iron.