刚玉-莫来石推板高温行为和显微结构

采用三点弯曲法对两种刚玉-莫来石推板产品的高温断裂强度和1400℃下的高温抗弯蠕变进行了对比研究.结果表明,进口推板材料具有较高的高温断裂强度和较好的高温抗弯蠕变性能,其结构特点是以红柱石颗粒为骨料,基质中形成良好的薄膜状莫来石结合刚玉的结构,玻璃相含量极低.国产推板尽管基质中莫来石已形成网络结构,但内部存在少量玻璃相,使得高温断裂强度较低,高温抗弯蠕变性较差.莫来石形态和玻璃相的存在是影响材料高温性能的决定因素.

High-temperature behavior and microstructure of corundum-mullite pushers

The high-temperature rupture strength and the bending creep behavior at 1 400 ℃ of two types of corundum-mullite pushers were investigated by three-point bending test. The results show that the pusher produced oversea which introduces andalusite as an aggregate has excellent microstructure. Corundum bonded by uniform mullite forms in the matrix and no glass phase is detected. This structure leads to high rupture strength and good bending creep resistance. For the pusher produced domestically,few glass phase leads to lower rupture strength and poor bending creep resistance at 1 400 ℃ though mullite forms a network in the matrix. The morphology of mullite and the glass phase are important factors which affect the high-temperature mechanical properties of a pusher.