This paper describes an experimental investigation of the cutting of Al-Ni alloys and tool wear mechanism to diminish severe tool wear in hypereutectic Al-Si alloys. These alloys contain softened second phase particles (intermetallic compound Al3Ni, HV=650) in comparison with primary Si hard particles (HV=1560) in hypereutectic Al-Si alloys. Summary of the results are shown below. (1) With increasing in Ni content in the alloys, number and area percentage of intermetallic compound particles increase. The cutting force components decrease gradually and the surface roughness become worse in higher Ni contained alloy. (2) The machinability and cutting temperature of Al-Ni alloys are determined to be the nearly same as those of hypereutectic Al-Si alloys. (3) Crushed and/or fine grained particles in Al-Ni alloys are almost not observed in cutting and torsion test due to the enriched plasticity of the matrix. (4) Tool wear of carbide tools in cutting of Al-Ni alloys are hardly observed within this work. These facts are attributed to smaller matrix force restricted for the particles and less frequency of mechanical scratching by hard particles for tool flank, in comparison of those of hypereutectic Al-Si alloys.