单边切口梁法测量建筑陶瓷砖的断裂韧性

Measurement of Fracture Toughness of Ceramic Tiles by Single Edge Notch Beam Method

建筑陶瓷砖是具有装饰性釉面的非均质材料,同时还具有背纹。研究了单边切口梁法制样条件如直通切口的宽度、深度、方向,以及建陶砖釉面和背纹等因素对断裂韧性测量的影响。结果表明当切口宽度<0.25 mm,切口钝化效应不明显;而切口宽度>0.4 mm断裂韧性测量值明显偏大。从釉面、坯体和侧面3个方向引入切口,可减少釉面和背纹的干扰,综合评价建陶砖的韧性。切深比a/W为0.3~0.6,对高吸水率的陶质砖和低吸水率的瓷质砖都可获得较为稳定的断裂韧性值。

Ceramic tiles are heterogeneous materials with decorative glazed surfacesas well as back patterns.Although single edge notched beam method(SENB)is widely used in structural ceramic materials,it is necessary to study the applicability of SENB method in ceramic tiles.In this work,the specimen preparation condition of SENB,such as the width,depth,direction of the notch,glaze and back patterns of ceramic tiles,are systematically studied.The results show that when the notch width is less than 0.25mm,less passivation effect is observed.However,the toughness measured is over-valuated with notch width>0.4 mm.In order to eliminate the interference caused by the glaze and back patterns,notches introduced from the three directions of glaze,body and side are recommended.When the notch depth to specimen width ratio a/Wis 0.3~0.6,more stable fracture toughness values can be obtained,whether fine earthenware tile with high water absorption or porcelain tiles with low water absorption.