Acoustic Emission and Indentation Fracture Method for the Engineering Ceramics

J. Ocean Eng. Technol. 2001;15(2):61-65.

세라미스 파괴인성평가에 있어서 IF법과 AE

김부안,문창권

부경대학교 재료공학부,부경대학교 재료공학부

Keywords: Engineering ceramics, Median crack, Acoustic emission, Fracture toughness, Elastic modulus, Vickers hardness, Indentation fracture

핵심용어: 구조용 세라믹스, 메디안 균열, 음향방출, 파괴인성, 탄성률, 비커스 경도, 인덱테이션 파괴

Abstract

The fracture toughness of ceramics can be measure by such various methods as DT (double torsion), CN (chevron notch) etc. But, the application of these methods to the engineering ceramics is very difficult because of its very high hardness. So, IF (indentation fracture) method is generally used for the evaluation of fracture toughness of ceramics. The Median crack induced by the sharp Vickers indenter was compared with the detected AE (acoustic emission) signal. On the silicon nitride ceramics, the AE test results agree fairly well with the median crack occurance and growth process. But, on the alumina, very many complicated crack signals were detected besides median crack. It can be considered that the IF methods must be used in limited engineering ceramics materials.