中文摘要：
	本研究的目的在探討受力模式與缺口效應對沃斯回火球墨鑄鐵高週疲勞性質的影響。研究的鑄件是採用T形鑄件以模擬齒輪鑄件，提供工業界參考。實驗結果顯示，就受力模式而言，彎矩受力模式所得的疲勞強度會比軸向受力模式高，這個現象與受高應力體積的大小有關，受高應力體積愈大，疲勞強度會降低，而不同缺口形狀下受缺口處應力集中的影響使疲勞強度降低的現象，也與受高應力體積的大小不同有關，疲勞強度也與衝擊韌性值有關；將不同熱處理、缺口形狀及受力模式等條件組合所獲得之ADI疲勞限，與衝擊韌性值及受高應力體積之間利用次冪定律(power law)之關係，可得到一預測ADI疲勞限的迴歸公式。
Abstract：
	This study investigated the factors that affect high-cycle fatigue (HCF) strength of austempered ductile iron (ADI). These factors include loading mode, notch effect, and highly stressed volume. Specimens were prepared in different notch geometries with stress concentration factors ranging from 1 to 2.64. HCF tests were conducted in both rotating-bending and uniaxial cyclic loading to determine the stress-life (S-N) curve for each specific condition. Results show that, on the effect of loading mode, the fatigue strength in rotating-bending is higher than that in axial loading because of the difference in highly stressed volume. The fatigue limit is decreased with an increase in the highly stressed volume. The degree of decrease in fatigue strength under different notch geometries can also be related to the effect of highly stressed volume. A prediction equation for the fatigue limit of ADI was introduced in terms of impact toughness and highly stressed volume.