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.