内氧化法制备MgO弥散强化铁基材料

Preparation of MgO dispersion strengthening ferrous materials by internal oxidation

采用机械合金化—低温表面氧化—高温内氧化—还原处理制备MgO弥散强化铁粉后再经放电等离子(SPS)烧结制备MgO弥散强化铁基材料,并通过SEM和EDS对材料的组织和断口进行分析。结果表明:添加MgO能够细化晶粒,并均匀地分布于基体中,MgO颗粒尺寸200nm^1μm。添加MgO强化后,材料的拉伸断口由粗大的韧窝变成细小的等轴韧窝;MgO弥散强化铁基材料烧结体的室温力学性能得到有效提高,Fe+1.0%MgO的抗拉强度为342.6MPa,屈服强度为276.3MPa,硬度为61HRB,相对于纯铁分别提高了20.5%、54.2%和84.8%。

The MgO dispersion strengthening iron powder was prepared by mechanical alloying, surface oxidation at low temperature, internal oxidation at high temperature and reduction treatment. Then the MgO dispersion strengthening ferrous material was fabricated by spark plasma sintering （SPS）. The analysis of SEM and EDS on the microstructure and fracture shows that the MgO particle size is 200 nm-1 μm and the MgO is uniformly distributed in the matrix which can refine the grain. The dimple fractures become smaller after the addition of MgO. The mechanical properties at room temperature of the Fe＋1.0%MgO are that, the tensile strength is 342.6 MPa, the yield strength is 276.3 MPa, the hardness is 61 HRB, which compared with pure iron are increased by 20.5%, 54.2% and 84.8% respectively.