碳含量对Fe-Cu-C扩散预合金粉末烧结性能的影响

Influence of carbon content on the properties of diffusion alloyed Fe-Cu-C sintered materials

扩散预合金化铁基粉末由于具有高的压缩性和成分均匀性而在粉末冶金零件中得到广泛应用。本文以扩散预合金化Fe-2%Cu(质量分数,下同)粉末为主要原料,研究了添加不同含量(0.4%、0.6%、0.8%、1.0%)的石墨粉后烧结Fe-Cu-C合金的显微组织、力学性能和尺寸变化率,并与相同成分的混合粉烧结坯进行对比。结果表明,随着碳含量的增加,Fe-Cu-C合金的烧结密度降低、硬度增加、尺寸变化率减小。扩散预合金粉末烧结后的组织更加均匀,硬度比混合粉烧结坯高5～6HRB,尺寸膨胀率仅为0.10%～0.20%,且尺寸稳定性优于混合粉烧结坯。

Diffusion alloyed ferrous powders are widely used in powder metallurgy parts because of their high compressibility and uniform chemical composition. The comparison of microstructure, mechanical properties and dimensional variability of sintered Fe-Cu-C steels with the diffusion alloyed Fe-2Cu powder as raw material and addition of different amounts of graphite to that of sintered steels with the same composition and mechanically mixed Fe and Cu powder as raw powder was investigated. The results indicate that the density and the dimensional expansion rate of sintered Fe-Cu-C steels decrease and the apparent hardness increases with the increasing carbon content. Sintered diffusion alloyed Fe-Cu-C steels show more uniform microstructure, 5 - 6HRB higher in hardness, and better dimensional stability than those of sintered mechanically mixed Fe-Cu-C steel.