SiC/W层状复合材料力学性能及显微结构分析

Analysis of Mechanical Properties and Microstructure for Laminated SiC/W Composites

以 Si C陶瓷片为基体层 ,金属 W为夹层 ,热压烧结制成 Si C/W层状复合材料。 X射线衍射分析显示 :夹层中的 W与 Si C反应生成了 W5Si3和 WC,无金属 W存在。断面扫描电镜分析表明 :(1 )夹层由颗粒状晶体 (W5Si3)和片状晶体 (WC)组成 ,片状晶片重叠为二级层状结构。 (2 )基体层 (Si C层 )的断裂方式为裂纹沿晶断裂 :夹层的断裂方式有两种 :一是裂纹沿颗粒状晶体的晶界的沿晶断裂 ,二是裂纹穿过片状晶体的穿晶断裂 ,断口还观察到片状晶片的拨出。材料力学性能呈现的规律为 :夹层厚度在 1 0～ 50 μm内 ,随夹层厚度的增加 ,断裂韧性增加 。

Using hot pressure technique, the laminated SiC/W compostites is made, The analysis of XRD showed that there was chemical reaction between W and SiC, W 5Si 3 and WC were produced, but there was not the W The analysis of SEM for fracture surface showed that some result have gotten, for example ① the layer be composed of grains state crystal (W 5Si 3) and slice stare crystal (WC), the slice state crystal reduplicate two rank laminated structuire ② the fracture form of basic layer (SiC layer) is along crystal fracture The fracture form of layer have two kind form, one is intergranular that crack is along grain boundary, other kind is intergranular fracture that crack pass throuugh slice state crystal We observe that the slice state crystal was pumped ouot The law of materials mechanical properties is that if thickness of layer is incremental, then the fracture toughness of laminated SiC/W composites is incremental and the resistance of bending strength is reducing in thickness 10~50μm