Abstract
In this report, Al-Si alloys which contain 2-25mass%Si was processed and machined by dry cutting in order to clarify effect of eutectic Si particles and primary Si particles on machinability of Al-Si alloy. The number of chips per unit weight was rapidly increased in machining specimens containing more than 15mass%Si. Moreover, Chip thickness and curl radius decrease with increasing the eutectic Si. It was found that these are due to higher hardness of matrix caused by eutectic Si particles. Therefore, it is considered that the crack of primary Si which act as a nucleus of chip breaking grow up, and thereby the increase of number of chips was promoted.
