Research And Simulation Prediction Of The Mechanical Properties Of Hard Brittle Materials Processing Surface

At present,with the rapid development of advanced manufacturing technology the hard brittle materials has been widely used in the field of high-tech.Especially,the non-metallic non-conductive materials and semiconductors,etc,has been more and more popularly used in the field of optical,electrical,aerospace,defense and civilian industries and other,and occupied a very important position.Hardness,Young’s modulus and fracture toughness,which are the basic parameters of the mechanical properties of materials,became the focus of this paper,and the reasonable prediction of the mechanical properties turned into the main point.For study and forecast the mechanical properties of the hard and brittle materials processed surface,the main work of this paper were: taking monocrystalline silicon as an example,prepared the hard and brittle materials sample model with different damage characteristics by ion implantation modification;obtained the surface mechanical properties of each sample by nano-indentation test;analyzed the surface of modified material samples by X ray diffraction and studied the mechanism of the change of sample surface mechanical properties;The hardness and fracture toughness were simulated and predicted based on the ABAQUS simulation software,and from the point of view of simulation influence of Young’s modulus,Poisson’s ratio and the maximum principal stress on the fracture toughness of materials were studied.The effects of Young’s modulus,Poisson’s ratio and the maximum principal stress on fracture toughness of materials were studied from the perspective of simulation.Through a large number of theoretical analysis and experimental simulation,the main results of this paper are as follows.(1)By ion implantation modified,taking single crystal silicon as an example,constructed a hard and brittle materials machining surface/subsurface damagemodel with different surface mechanical properties,and the mechanical propertiesof the samples were studied with the aid of the nano-indentation test and X-raydiffraction(XRD),which showed the prototype has reached the expected damageinduced modification effect of surface mechanical properties of different parts werechanged,and the surface / subsurface damage model of hard brittle materials wassuccessfully constructed.(2)The hardness of the material is simulated and forecasted by ABAQUS.The simulation results are in good agreement with the experimental results,which verified the correctness and effectiveness of the established hardness simulating predicting model(3)Based on ABAQUS XFEM module,combined with the material models and extrapolation,the fracture toughness of samples were predictive simulation.The consistency of the monocrystalline silicon’s predicted values between actual data,demonstrated the effectiveness of the prediction model of fracture toughness.(4)By using fracture toughness prediction simulation model and the controlling variable method,the effects of the young’s modulus,Poisson’s ratio and the maximum principal stress on fracture toughness of materials were studied.It is found that the Young’s modulus has no effect on the fracture toughness of the material,and Poisson’s ratio has limited influence on the fracture toughness.The maximum principal stress is the main factor affecting the fracture toughness.