La2O3-TiC/W复合材料组织结构与力学性能

采用真空热压烧结法制备La₂O₃-TiC/W复合材料，并对其组织结构和力学性能进行了研究。结果表明：在一定成分范围内，La₂O₃和TiC的加入提高了复合材料的力学性能，La₂O₃和TiC共同作用时的强化效果强于La₂O₃和TiC单独作用的强化效果，但La₂O₃-TiC/W复合材料的密度和相对密度随TiC含量的增加而下降，并进而影响硬度和弹性模量的提高， 适量的La₂O₃有益于相对密度的提高；抗弯强度在1%La2O3 5%TiC/W成分含量时出现最大值901MPa，而断裂韧性在成分含量为0.5%La₂O₃-10%TiC/W时出现最大值10.07MPa·m1/2。本研究中，1%La₂O₃-5%TiC/W成分配比时具有较好的综合力学性能。La₂O₃-TiC/W复合材料的强化机制为细晶强化和载荷传递，韧化机制为细晶韧化、裂纹偏转和桥接。

Structure and mechanical properties of La2O3-TiC/W composites

The tungsten based composites, co-strengthened by La2O3and TiC with different contents, were prepared by the powder metallurgy method. The structure and mechanical properties at room temperature of La2O3-TiC/W composites were investigated. The results show that addition of La2O3 and TiC improves the mechanical properties of tungsten composites. The co-strengthening effect of La2O3 and TiC is better than that of La2O3 or TiC. Density and relative density of La2O3-TiC/W composites decrease with increasing the TiC content, which influences the hardness and elastic modulus of the composites. La2O3 with appropriate content is beneficial to improvement of relative density. The flexural strength has a maximum of 901MPa with composition of 1% La2O3-5% TiC/W, and fracture toughness has a maximum of 10.07 MPa·m1/2 with composition of 1% La2O3-10% TiC/W. In this experiment, the La2O3-TiC/W composite has optimal mechanical properties with addition of 1wt% La2O3and 5wt%TiC. The strengthening mechanisms of La2O3-TiC/W composite are fine grain strengthening and load transferring.The toughening mechanisms are fine grain toughening, crack deflection and microbridging.