镍-石墨高温自润滑材料的熔炼制备及其组织性能

采用真空中频感应熔炼、电弧熔炼和高频感应熔炼辅助3 m落管无容器快速凝固方法,制备出镍-石墨两相自润滑合金.研究表明:在石墨型中浇铸,石墨呈片状生长;在金属型中浇铸,石墨有球化趋势;在电弧炉中熔炼并凝固,石墨基本呈球状组织形态,在3 m落管中经深过冷快速凝固后石墨呈球状组织.从而得出,石墨在生长过程中,(1010)棱面与(0001)基面的再辉温度差是影响石墨生长形态的重要因素.该材料具有高的冲击韧性和较低的电阻率,与45#退火钢及GCr15轴承钢干摩擦磨损时,摩擦因数分别稳定在0.23和0.15.

Preparation and structure property of high-temperature self-lubricating Ni-graphite alloy by melting method

Self-lubricating two-phase Ni-graphite alloy was produced by methods of vacuum medium-frequency induction melting, arc melting and containerless rapid solidification process of 3m drop tube assisted by high-frequency induction melting. The results show that graphite cast in graphite mold grows in lamellar shape; graphite cast in metal mold tends to be spheroidized; graphite smelting and solidifying in arc furnace is in globular shape, and homogeneous globular graphite is achieved in rapidly-solidified alloy prepared by 3m drop tube. It has been presented that the recalescence temperature difference between (1010)edge plane and (0001)basal plane of graphite in graphite growing procedure is an important influencing factor on the growth morphology of graphite. The Ni-graphite alloy shows high impact flexibility and low electrical resistivity. Through dry friction and wear experiment against 45~# steel and GCr15, it is found that the friction coefficient of the alloy stably remains 0.23 and 0.15, respectively.