磨削对结构陶瓷缺陷区域的损伤作用

GRINDING DAMAGE IN MATERIAL DEFECT AREAS OF STRUCTURAL CERAMICS

陶瓷缺陷区的加工损伤是导致材料失效的主要原因之一。本文通过对 Al2 O3 、Si3 N4 和 Mg-Zr O2 结构陶瓷的磨削试验研究 ,分析了磨削对气孔、疏松及晶粒间界这类缺陷区域的损伤作用。结果表明 ,磨削对晶粒内小气孔和大气孔区域的损伤作用都很小 ;而在疏松及晶界区域会产生危害明显、尺寸较大的塌坑和磨削微裂纹。

A variety of damages, especially, damages in the defective areas of materials,that are derived from the machining process appear as one of the important reasons, leading to faults in ceramic parts in their application. By grinding test and SEM analysis on the ground surface of structural ceramics Al2O3, Si3N4, and Mg-ZrO2 et al, damaging actions in the grinding process upon defective of areas ceramics such as pore, looseness, crystal boundary and interstice are investigated. It is shown that there is little effect by grinding on the microstructure of fine pores inside crystals,and that grinding damages in large pores, whether rounded or irregular, are negligible. However, remarkable subsidence and micro-cracks are produced in areas of looseness and crystal boundaries during grinding, which are detrimental to the mechanical properties of ceramic materials.