ADI의 미세조직과 기계적 특성에 미치는 특수열처리 및 합금원소의 영향 = Effects of Special Heat Treatments and Alloying Elements on the Microstructures and Mechanical Charateristics of ADI

다국어 초록 (Multilingual Abstract)

The effects of heat treatments and alloying elements on the microstructure and mechanical characteristics of specially austem-pared ADIs containing alloying elements such as Cu, Mo and Ni were investigated. To compare with the effect of conventional and normal(CN) austempering treatment, two kinds of special austempering treatments which pre-quenching and pre-heating were conducted. The hardness and uniaxial fatigue tests were carried out to evaluate the mechanical characteristics. The hardness of ADI treated by CN heat cycles was higher than those of other ADIs. Cu added ADI(Cu-ADI) tempered at 400 after austenitizing exhibited the highest fatigue life cycles. While austempering after prequenching makes the austenite with high carbon stable, which resulted in transformation to highly strengthened bainites from the carbon enriched austenite phases during tempering. The high carbon enriched banites is considered to improve the fatigue strength.(Received January 5, 2002)