Finite Element Investigation of the Influence of SiC Particle Distribution on Diamond Cutting of SiCp/AI Composites

Characteristics of internal microstructures have a strong impact on the properties of particulate reinforced metal composites.In the present work,we perform finite element simulations to elucidate fundamental mechanisms involved in the ultraprecision orthogonal cutting of aluminum-based silicon carbide composites(SiCp/AI),with an emphasis on the influence of particle distribution characteristic.The SiCp/AI composite with a particle volume fraction of 25 vol%and a mean particle size of 10|im consists of randomly distributed polygon-shaped SiC particles,the elastic deformation and brittle failure of which are described by the brittle cracking model.Simulation results reveal that in addition to metal matrix tearing,cuttinginduced particle deformation in terms of dislodging,debonding,and cracking plays an important role in the microscopic deformation and correlated machining force variation and machined surface integrity.It is found that the standard deviation of particle size to the mean value has a strong influence on the machinability of microscopic particle-tool edge interactions and macroscopically observed machining results.The present work provides a guideline for the rational synthesis of particulate-reinforced metal composites with high machinability.

Cutting path-dependent machinability of SiCp/Al composite under multi-step ultra-precision diamond cutting

Particle-tool interactions,which govern the synergetic deformation of SiC particle reinforced Al matrix composites under mechanical machining,strongly depend on the geometry of particle position residing on cutting path.In the present work,we investigate the influence of cutting path on the machinability of a SiCp/Al composite in multi-step ultra-precision diamond cutting by combining finite element simulations with experimental observations and characterization.Be consistent with experimentally characterized microstructures,the simulated SiCp/Al composite is considered to be composed of randomly distributed polygonally-shaped SiC particles with a volume fraction of 25 vol%.A multi-step cutting strategy with depths of cut ranging from 2 to 10 lm is adopted to achieve an ultimate depth of cut of 10 lm.Intrinsic material parameters and extrinsic cutting conditions utilized in finite element simulations of SiCp/Al cutting are consistent with those used in corresponding experiments.Simulation results reveal different particle-tool interactions and failure modes of SiC particles,as well as their correlations with machining force evolution,residual stress distribution and machined surface topography.A detailed comparison between numerical simulation results and experimental data of multi-step diamond cutting of SiCp/Al composite reveals a substantial impact of the number of cutting steps on particle-tool interactions and machined surface quality.These findings provide guidelines for achieving high surface finish of SiCp/Al composites by ultra-precision diamond cutting.