关键词: 70%Si/Al合金, 铣削力, 刀具磨损, 加工损伤机理

Abstract: Due to the large amount of silicon particles，the machinability of the high-volume fraction silicon aluminum alloys was poor.Severe tool wear and deteriorated machined surfaces with defects were major problems in cutting high-volume fraction silicon aluminum materials.To further explore the machining damages，the milling experiments of 70% Si/Al（mass fraction is 70%）alloy were carried out，where the tools were prepared by chemical vapor deposition（CVD）method.Milling force，tool wear and mechanism of machining damages were investigated.As a comparison，milling tools with TiN coating were also utilized under identical cutting parameters.The results show that the main tool wear modes of the diamond coated tools are coating peeling and abrasive wear，which are due to the impact and scratching of hard silicon particles in milling processes.In the normal wear stages of the diamond coated tools，the milling force is stable in the range of 4357～4895 N，while the milling force of TiN coated tools is higher and the tool life is shorter.The damages on machined surfaces are mainly pits，scratches and ruptured particle.Under the premise of ensuring the strength of cutting-edge radius，machining damage may be obviously reduced by reducing the radius of tool cutting-edge.The surface roughness value（Sa=23 μm）machined with a cutting-edge radius of 12 μm is lower than that with a radius of 156 μm（Sa=67 μm）.

Key words: 70% Si/Al alloy, milling force, tool wear, mechanism of machined damage