铝粉、硅粉加入比例对Al_2O_3-ZrO_2-C材料力学性能的影响

Effects of adding ratio of Al and Si on mechanical properties of Al_2O_3-ZrO_2-C refractory materials

在A l2O3-ZrO2-C材料中加入总质量分数为5%的铝粉和硅粉,改变试样中铝粉和硅粉的质量比(分别为0:1、1:4、2:3和4:1),经配料、混练、成型、烘干后,在埋炭(煤焦炭)气氛中分别于800、1 000、1 300和1 400℃保温3 h煅烧,然后对烧后试样进行三点弯曲试验,并测定烧后试样的平均孔径,分析烧后试样的显微结构。结果表明:铝粉、硅粉的加入比例显著影响A l2O3-ZrO2-C材料的力学性能:经800和1 000℃煅烧后,试样的抗折强度、弹性模量和韧性均随铝粉加入量的增加而增大,而经1 300和1 400℃煅烧后,试样的抗折强度、弹性模量和韧性均随铝粉加入量的增加而减小;试样的平均孔径呈现出与力学性能相反的变化规律。上述这些变化规律是铝液的促烧结作用与高温下生成SiC、A lN晶须的强韧化作用和填隙作用以及生成A lN过多导致的结构疏松作用共同作用的结果。

Al2O3-ZrO2-C refractory materials were added by 5% of total amount of aluminum powder and silicon powder but with varied adding ratios （0 ： 1, 1：4,2：3 ,and 4 ： 1 ）. Specimens were prepared by weighing, mixing,pressing,curing,and firing in coke bed at 800,1 000,1 300, and 1 400 ℃ for 3 h, respectively. The three points bending test of fired specimens was conducted, the average pore diameter was determined, and the microstructure was observed. The results show that the impact on mechanical properties of Al2O3- ZrO2-C refractory materials from the adding ratios of Si and AI is remarkable：the modulus of rupture,elastic modulus,and toughness of specimens fired at 800 and 1 000℃ increase with AI powder addition increasing,those of specimens fired at 1 300 and 1 400 ℃ decrease with AI powder addition increasing;the pore size distributions of specimens present opposite trend against the mechanical properties. These clear trends are contributed by the sintering acceleration effect of AI liquid, the toughness improvement and structure densification from SiC and AIN whiskers,and the volume loosening from superabundant AIN.