W-10%TiC复合材料的制备与力学性能研究

Study on Preparation and Mechanical Properties of W-10%TiC Composites

采用高能球磨手段制备了W-10%TiC(质量分数,下同)纳米复合粉体,并采用热压方法烧结成致密块体,研究了高能球磨、烧结温度、烧结时间及烧结压力对复合材料致密度和力学性能的影响。结果表明:高能球磨后,复合粉体的颗粒形状近似球形,粒径均匀,平均粒径为100nm,并且纳米复合粉体的烧结温度大大降低,其原因是粉体的颗粒细小、扩散系数高、表面能高等性质及球磨过程中少量Fe,Ni杂质的引入。对所制备纳米粉体而言,较合适的烧结工艺为:1700℃,30MPa压力下烧结60min,在此工艺条件下制备的复合材料的致密度达到98.4%,抗弯强度和断裂韧性分别达到:681MPa,6.24MPa·m1/2。

W-10%TiC composites were prepared by high energy ball milling and vacuum hot-pressing （VHP） and sintering. The effects of high energy milling, sintering temperature, holding time and hot pressure on the composites were investigated. The results show that the nanocomposite powders with homogeneous particle size about 100 nm were obtained through high energy milling processing. The nanocomposite powders were consolidated to bulk with high density at low temperature, which was caused by the fine particles having high diffusion coefficient, high surface energy and the impurity of Fe, Ni introduced from the process of high energy milling. The relative density, flexural strength and fracture toughness of the composites prepared under the optimal condition 1700 ℃, 30 MPa for 60 min could reach to 98.6%, 681 MPa and 6.24 MPa·m^1/2, respectively.