[Microstructure analysis of the machinable infiltrated ceramic fracture surface].

Objective: To compare the fracture surface of the machinable infiltrated ceramic (MIC) prepared in different conditions, and to relate its strength and toughness to the differences in their microstructures.

Methods: The Al2O3 matrix were prepared, infiltrated by the machinable glass and crystallized. Based on sintering and infiltrating time and conditions, the specimens were divided into three groups: Perfect group, insufficiently infiltrated group, mal-sintered substrate group. Specimens were fabricated, three point flexural strength and elastic modulus were tested, and the microstructure of the MIC fracture surfaces was analyzed by means of scanning electron micrograph (SEM) observation.

Results: The strength of the insufficiently infiltrated group and mal-sintered substrate group were lower than that of the perfect group, and faults in the microstructure of these two groups also proved this. The foreland of glass infiltrating in the Al2O3 and the interface of glass and complex demonstrated that the Al2O3 surface was smoother than the complex and there was a big crack in the glass but not in the complex which proved the crack resistibility of glass and Al2O3 were smaller than that of the complex (MIC).

Conclusion: Correct preparing process could make the glass infiltrate into properly sintered Al2O3 sufficiently which ensured best mechanical properties of the complex.