复合稀土氧化物掺杂W-20Cu复合材料的制备及组织性能研究

以偏钨酸铵和硝酸铜为原料,采用EDTA-柠檬酸法制备了含有0~0.8wt.%稀土氧化物( Ce_0.8Sm_0.2O_1.9, SDC)的W-20Cu复合粉体,所制备的复合粉体经压制成型、1250°C烧结2h后获得SDC/W-20Cu复合材料烧结体。对所制备复合粉体进行物相、形貌的表征；研究稀土氧化物的添加对SDC/W-20Cu烧结体的密度、组织结构和物理力学性能的影响。实验结果表明：所制备的W-Cu复合粉体平均粒度为100~200nm；同时,SDC的添加对烧结体的密度和电导率会有轻微的影响,但能够抑制晶粒的长大并明显改善烧结体的力学性能。经1250°C烧结后,SDC/W-20Cu烧结体的相对密度均高于97%；当SDC的添加量为0.6%时,具有最大的抗弯强度和显微硬度,分别是1128MPa和258HV；此外,在室温和600°C的测试条件下,其最大的抗拉强度可以达到580MPa和258MPa。

Preparation and properties of ultrafine grain W-20Cu composites doped with rare earth oxides

Ultrafine W-20wt.%Cu(W-20Cu) powders doped with 0-0.8 wt.% rare earth oxides Ce_0.8Sm_0.2O_1.9, (SDC) were synthesized by the EDTA-citrate method using ammonium meta-tungstate and copper nitrate as raw materials, and the resultant powders were pressed and sintered at 1250°C in H₂ atmosphere for 2h to obtain SDC/W-20Cu composites. Morphology of the SDC/W-20Cu powders and microstructure of the sintered SDC/W-20Cu composites were observed by SEM, and density, physical and mechanical property of sintered SDC/W-20Cu composites were also tested to investigate the influence of rare earth addition. The results show that the SDC/W-20Cu powders have irregular shape with particle size ranging from 100 to 200 nm. The addition of SDC has slight influence on the electrical conductivity, but obviously refines the grain size and improves the mechanical properties of the W-20Cu composites. The sintered SDC/W-20Cu samples have relative density above 97%. Bending strength and micro-hardness of the SDC/W-20Cu specimens are 1128MPa and 318HV with the addition of 0.6wt.% SDC, respectively, and the highest tensile strength reaches 580MPa and 258MPa at room temperature and 600°C, respectively..