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以化学纯镍粉、钛粉、铝粉、石墨粉为原料,采用燃烧合成方法制备了TiC/Ni3Al含孔预制件,用无压熔渗法制备了TiC/Ni3Al复合材料。对TiC/Ni3Al复合材料的微观组织、硬度和断裂韧性进行了研究并采用XRD和SEM分析了复合材料的相组成、微观结构、断口形貌。采用压痕法计算了TiC/Ni3Al复合材料的断裂韧性。试验结果表明:无压熔渗法是制备致密的TiC/Ni3Al复合材料的有效方法。在完成渗透获得致密组织的前提下,渗透温度和渗透时间对TiC/Ni3Al复合材料的硬度及断裂韧性无显著影响。渗透后复合材料的组成相主要为Ni3Al和TiC两相,Ni3Al相和TiC颗粒结合良好。本文制备的Ni3Al/TiC复合材料的维氏硬度随TiC体积分数的增加而增加,TiC含量分别为70%和80%时,复合材料的维氏硬度平均值分别为569.6(Hv)和610.8(Hv)。复合材料的断裂韧性最高达到了10.5MPa.m1/2,TiC颗粒和Ni3Al界面的分离是复合材料断裂过程中存在的主要失效形式。断裂过程中Ni3Al可以有效地吸收裂纹扩展能量,阻止了裂纹的直线扩展,使裂纹扩展方向发生偏转,大大增加了材料的断裂韧性。
The TiC / Ni3Al porous preform was prepared by combustion synthesis method using chemically pure nickel powder, titanium powder, aluminum powder and graphite powder as raw materials, TiC / Ni3Al composites were prepared by pressureless infiltration method. The microstructure, hardness and fracture toughness of TiC / Ni3Al composites were studied and the phase composition, microstructure and fracture morphology of the composites were analyzed by XRD and SEM. The fracture toughness of TiC / Ni3Al composites was calculated by indentation method. The experimental results show that pressureless infiltration method is an effective method for preparing compact TiC / Ni3Al composites. The infiltration temperature and infiltration time had no significant effect on the hardness and fracture toughness of the TiC / Ni3Al composites under the premise of achieving the infiltration of dense tissue. The composition of the composite after infiltration is mainly Ni3Al and TiC two phases, Ni3Al phase and TiC particles combine well. The Vickers hardness of Ni3Al / TiC composites increases with the increase of volume fraction of TiC. The average Vickers hardness of composites is 569.6 (Hv) and 610.8 (Hv) when TiC contents are 70% and 80% ). The fracture toughness of the composites reaches up to 10.5MPa.m1 / 2. The separation of TiC particles and Ni3Al interface is the main failure mode during the fracture of the composites. During the fracture process, Ni3Al can effectively absorb the crack propagation energy, prevent the linear expansion of the crack, and cause the crack growth direction to deflect, which greatly increases the fracture toughness of the material.