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新型自润滑模具材料的制备和高温性能研究

Preparation and high temperature properties of new self-lubricating die materials

  • 摘要:以铁镍基合金为基体, 添加硬质相Cr 2O 3及固体润滑剂CaF 2, 利用粉末冶金工艺制备了高温自润滑热锻模具材料。采用X射线衍射仪、扫描电子显微镜及显微硬度计, 研究了烧结工艺对铁镍基自润滑材料力学性能的影响, 分析了Cr 2O 3和CaF 2对铁镍基自润滑材料烧结性能的影响, 并得到了最佳烧结工艺。结果表明: 当烧结工艺为1320℃、保温2 h时, 制备得到的铁镍基自润滑材料力学性能优越; 硬质相Cr 2O 3质量分数从0增加到30%, 试样相对密度下降4.0%, 硬度从HV 227.3增加到HV 342.8;固体润滑剂CaF 2质量分数从0增加到10%, 试样相对密度和硬度均下降; 通过600℃摩擦磨损实验发现, 随CaF 2质量分数的增加, 试样摩擦系数和磨损率先降低后升高; 当添加质量分数20% Cr 2O 3和8% CaF 2时, 自润滑模具材料的综合性能最佳。

    Abstract:A new high-temperature self-lubricating die materials was prepared by powder metallurgy using Fe-Ni alloy as the base materials, Cr 2O 3as the hard phase, and CaF 2as the solid lubricant. The effects of sintering process on the mechanical properties of Fe-Ni-based self-lubricating materials were investigated by X-ray diffractometer, scanning electron microscope, and microhardness tester, the influences of Cr 2O 3and CaF 2on the sintering properties of the self-lubricating materials were studied, and the optimum sintering process was obtained. The results show that, the self-lubricating materials sintered at 1320℃ for 2 h exhibit the excellent mechanical properties. When the content of Cr 2O 3by mass increases from 0 to 30%, the relative density of the sample decreases by 4.0%, and the hardness increases from HV 227.3 to HV 342.8. When the content of CaF 2by mass increases from 0 to 10%, the relative density and hardness of the sample gradually decrease. With the increase of CaF 2content by mass in the friction and wear test at 600℃, the friction coefficient and wear rate decrease first and then increase. The self-lubricating die materials show the best combination performances as the Cr 2O 3content of 20% and the CaF 2content of 8% by mass.

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