高强度高韧性云母微晶玻璃的热压制备和力学性能

PREPARATION AND MECHANICAL PROPERTIES OF MICA GLASS CERAMICS WITH HIGH STRENGTH AND FRACTURE TOUGHNESS BY HOT PRESS

采用热压形变工艺，成功地制备出了具有择优取向的高强度高韧性云母微晶玻璃。用三点弯曲法和单边切口梁（ＳＥＮＢ）法在不同工艺条件下对微晶玻璃的抗弯强度和断裂韧度进行了测定。结果表明：在热压形变过程中，玻璃相发生粘性流动，云母晶体随之转动并产生择优取向，增强了对平行于热压方向的裂纹的偏转和分叉作用，材料的力学性能得到显著提高。基础玻璃在９５０℃晶化３ｈ并经１０００℃热压形变处理后，所得的云母微晶玻璃在热压方向上的抗弯强度和断裂韧度分别可达３９０ＭＰａ和２．９２ＭＰａ·ｍ１／２，比热压前提高了２倍多。

A novel type of preferentially oriented mica glass ceramic is fabricated by hot press deformation technique.The flexural strength of the glass ceramics heat treated with different process is measured by three point bending method and the fracture toughness of them was also determined by single edge notch beam(SENB)method.The results indicated that the residual glass phase flow viciously and mica crystals roll in the process of hot press,resulting in the preferentially oriented microstructure,which is more efficient to deflect and branch the crack propagating along the hot press direction.Thus the flexural strength and fracture toughness are improved significantly.The sample crystallized at 950℃ for 3h and hot pressed at 1000℃ shows good mechanical properties parallel to the hot press direction with the flexural strength of 390MPa and the fracture toughness of 2 92MPa·m 1/2 ,as two to three times as those of the sample without hot pressing treatment