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采用熔炼法制备了Fe-xAl-4.0C-3.5Si(x=6.3,7.4,8.9,11.1)系高温固体自润滑材料,研究了Al加入量对合金组织、力学性能及摩擦磨损性能的影响。结果表明:随着Al加入量的降低,合金中α-Fe(Al)固溶体的量增多,Fe3AlC0.5化合物的量减少,有利于改善材料的冲击韧度并提高合金的三点弯曲强度。Al加入量越少,凝固组织中石墨的面密度越大,可以减弱Al对液态合金中碳原子的排斥作用,有利于减小摩擦因素。其中Fe-7.4Al-4.0C-3.5Si合金因具有高的石墨面密度和Fe3AlC0.5硬质相均匀分布的组织特点,其耐磨与减摩性能最好,经900℃、15h退火处理后,摩擦因数保持在0.32的较低水平,磨损率是QT400-18L球墨铸铁的1/5。
The high-temperature solid self-lubricating Fe-xAl-4.0C-3.5Si (x = 6.3,7.4,8.9,11.1) system was prepared by the melting method. The effects of Al addition amount on the microstructure, mechanical properties and friction and wear properties of the alloy were investigated. The results show that the amount of α-Fe (Al) solid solution increases and the amount of Fe3AlC0.5 compound decreases with the decrease of Al content, which is beneficial to improve the impact toughness and the three-point bending strength of the alloy. The smaller the amount of Al is added, the larger the areal density of the graphite in the solidified structure can reduce the repulsion of Al to the carbon atoms in the liquid alloy and reduce the friction factor. The Fe-7.4Al-4.0C-3.5Si alloy has the best wear-resistance and friction-reducing properties because of its high surface area density of graphite and uniform microstructure of Fe3AlC0.5 hard phase. After annealing at 900 ℃ for 15h , The friction coefficient remains at a low level of 0.32, the wear rate is 1/5 of QT400-18L ductile iron.