Fracture toughness of Si3N4 processed by gas pressure sintering and hot pressing

Abstract

This present work evaluates the influence of microstructure on the fracture toughness of two types of silicon nitride. The two microstructural types of silicon nitride were processed using the gas pressure sintering (GPS) and hot pressing (HP) pathways. The fracture toughness was measured using the Single Edge V-Notch Beam (SEVNB) and Chevron Notch Beam (CNB) methods. The results from both methods for the two forms were in close agreement (with a maximum variation of 5.8%); the K Ic of the material processed by HP was 35% higher than that of GPS and the grain length had a direct influence on the fracture toughness

Sinterização e caracterização mecânica e microestrutural de cerâmicas de SiC aditivadas com misturas de AIN/Dy2O3 e AIN/Yb2O3

“…Os principais métodos existentes atualmente para a determinação de K Ic são listados a seguir: IF (Indentation Fracture -fratura por indentação) (72)(73)(74)(75)(76)(77)(78)(79)(80)(81)(82)(83)(84)(85)(86) , IS (Indentation Strength -resistência à indentação) (74,78,79,83,87) , CNB (Chevron Notch Beam -barra entalhada Chevron) (78,79,84,(87)(88)(89)(90)(91) , SCF (Surface Crack in Flexure -superfície da trinca em flexão) (78,79,83,84,88,89,91) , SEPB (Single Edge…”

“…Apesar de que em países europeus o método SEVNB já seja mais utilizado, no Brasil são poucos os artigos publicados sobre a tenacidade à fratura determinada por este método (56,72,91,111,112) .…”