フェライト基地球状黒鉛鋳鉄の片側きれつ曲げ試験による破壊挙動

概要

論文の詳細を見る
Fracture toughness tests on ferritic iron composed of a single phase matrix and graphite nodules were carried out using three types of test bars different in size to clarify the role of graphite nodules in fracture. Electron microscopic fractography was also made particularly on the feature of blunting and stable crack growth. The fraction of graphite nodules against ferrite matrix exceeds 50% at pre-crack tips. The ferrite matrix is divided into 25μm length each by graphite nodules. The critical width of stretched zone (SZWc) in this work is at most 15μm. Large dimples associated with graphite nodules are interceptors of stretched zone. SZW is independent of the size of test bars and of observing position on the fracture surface. Similarly, the values of fracture toughness determined by R-curve method with three different sizes of test are nearly the same. The region of stable crack growth almost consists of large dimples associated with graphite nodules.
Japan Foundry Engineering Societyの論文