铁基粉末冶金制件烧结时纳米铜在界面的作用

Effect of nano-copper on the interface in the process of sintering Fe-base powder metallurgy parts

为研究微量纳米铜添加到铁基粉末冶金件中烧结时对粒界扩散的作用.试验选择添加0.5%纳米铜的铁基粉末,通过高能球磨混合压制成样品,分别在不同温度相同保温时间及相同温度不同保温时间进行烧结,将上述试样冲击产生断口,通过SEM观察断口上纳米铜形貌变化.结果表明,纳米铜在铁基粉末冶金制品烧结过程中,保温时间相同随烧结温度升高和在相同烧结温度下随保温时间的延长在界面上发生快速吸附、溶解和扩散,使其团聚长大,在较低温度溶解于铁基粉末颗粒表面,明显降低烧结温度,由传统的工艺温度1180℃降低到920℃.

The effect of nano-copper powder on grain boundary diffusion of Fe-base powder metallurgy parts was investigated. The tested samples with the addition of 0.5% nano-copper powder and Fe-base powder were mixed by high-energy ball milling and then were sintered at different temperatures and temperature keeping time. The change of nano-copper morphology of impact fracture surface was observed by scan electrical microscopy （SEM）. Results show that nano-copper panicles exhibit rapid adsorption, diffusion and dissolution at Fe-base powder particle interface with the increased sintering temperature at the same temperature keeping time and the extended temperature keeping time at the same sintering temperature, which results in the accumulation and growth of nano-copper panicles. The nano-copper panicles are dissolved at the nano-Fe powder surface at low sintering temperature, and decrease the sintering temperature from 1180℃ to 920 ℃.