Fatigue Limit Estimation of Aluminum Die-casting Alloy by Means of ã‚‚’‚…‚ Method
Akira UENO, Masahide NISHIDA, Susumu MIYAKAWA, Koji YAMADA and Shoichi KIKUCHI
Abstract:In order to evaluate quantitatively the effects of casting defects on the fatigue properties of aluminum die-casting alloy, a fatigue limit estimation for aluminum die-casting alloy (JIS ADC12) containing large casting defects was proposed by means of ã‚‚’‚…‚ method. Fatigue tests were performed in ambient air by means of a dual spindle type rotating bending fatigue testing machine for two types of the specimen; one is an hourglass type specimen and the other is a smooth specimen having four artificial drilled holes whose ã‚‚’‚…‚ were ranged from 300 to 2000 ƒÊm on the surface. After fatigue tests, fracture surfaces and artificial defects were observed using an optical microscope and a scanning electron microscope (SEM). As results, all hourglass type specimens failed from casting defects. In the case of the smooth specimen having four artificial drilled holes, fatigue limit tended to decrease as artificial defects became large. According to the fatigue limits of the hourglass type specimen and of the straight type specimens having four artificial drilled holes, fatigue limit estimation for aluminum die-casting alloy was proposed by means of modified ã‚‚’‚…‚ method. In addition, it was clarified that the proposed equations for JIS ADC12 could estimate fatigue limits of another type aluminum die-casting alloys, JIS ADC10-T6. Key Words:Fatigue, Aluminum die-casting alloy, Casting defects, ã‚‚’‚…‚ method, Fatigue limit estimation