烧结温度对ZrC-Y_2O_3复合增强细晶钨组织与性能的影响

Effect of sintering temperature on properties and microstructure of tungsten composites reinforced by ZrC-Y_2O_3 particles

采用湿化学法制备W-3%ZrC-0.3%Y_2O_3（质量分数）材料,研究该材料在1800~1920℃的烧结致密化行为,通过与W-3ZrC材料及纯钨材料烧结态力学性能和显微组织的对比研究,分析复合添加ZrC和Y_2O_3对钨材料强韧化的作用和意义。结果表明：W-ZrC-Y_2O_3材料的致密度和抗拉强度均呈现出随烧结温度升高先增加后降低的趋势,其相对密度和抗拉强度均在1860℃达到最大值,分别为97.8%、446 MPa;添加第二相粒子能有效细化钨材料的晶粒,Y_2O_3/ZrC复合添加较单一ZrC能更有效细化钨晶粒,晶粒由W-3ZrC的10μm降低至5~8μm。复合强化相粒子改变了断裂过程中裂纹扩展的形状和长度,起到强化和韧化作用。

The composite materials of W-3%ZrC-0.3%Y_2O_3（mass fraction） were prepared by wet chemical methods. The densification behavior was studied when the composite materials was sintered at 1800-1920 ℃. By comparing with mechanical properties and microstructure of W-3ZrC materials and pure tungsten material, the function and meaning of compounding adding ZrC and Y_2O_3 were researched. The results show that the relative density and intensity increase at first, and then decrease with increasing sintering temperature. And the relative density and tensile strength reach 97.8% and 446 MPa, respectively, when sintered at 1860 ℃. The second phase particles can effectively refine the grain size of tungsten material, and the composite adding Y_2O_3/ZrC is more effective. The grain decreases from 10 μm of W-3ZrC to 5-8 μm of W-3ZrC-0.3Y_2O_3. The composite strengthening phase particles can change the shape and length of crack propagation, which proves that ZrC and Y_2O_3 are helpful to improve the strength and toughness of composites.