张苗苗 1侯荣国 2吕哲 1孙浩程 1崔焕勇 1云昊1
作者信息
- 1. 山东理工大学 机械工程学院,山东 淄博 255000
- 2. 山东理工大学 机械工程学院,山东 淄博 255000||山东省精密制造及特种加工重点实验室,山东 淄博 255000
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摘要
Abstract
Abrasive water jets are used to impact the surface of SLM-formed AlSi10Mg alloys,so as to reduce the stress concentration,microcracks and other defects on the surface of the alloy materials and improve the surface properties of the alloys.The work aims to study the abrasive water jet impact strengthening process and its strengthening mechanism by combining numerical simulation and experiment.Firstly,an abrasive water jet impact strengthening model was established based on the explicit kinetic model and the J-C material ontology,and the study was carried out from single-grain abrasive and multi-grain abrasive,respectively.By establishing a single-grain abrasive impact reinforcement model and calculating the number of abrasive particles at 100%coverage under different process parameters,the relationship between the process parameters and the coverage of the impact area was determined.Based on the requirement of 100%coverage,the uniform function in Python was used to establish randomly distributed abrasive particles in a specific space,numerically simulate the deformation process of abrasive water jet impacting on the surface of AlSi10Mg alloy,obtain the stress-strain distribution law on the surface of the alloy,and analyze the effect of the process parameters on the stress-strain distribution law,and validate the numerical model through relevant experiments.The feasibility of the numerical model was verified by relevant experiments.In the numerical simulation process,by changing the process parameters of abrasive water jet reinforcement,the plastic strain of the surface of the workpiece and the jet pressure and abrasive grain size of the law of change were obtained and the jet pressure for the surface of the workpiece plastic strain had the greatest effect followed by the abrasive grain size.Secondly,the experimental study of abrasive water jet impact strengthening was carried out,and the post-mixed abrasive water jet method was used in the experiments,and the experimental variables were jet pressure and abrasive grain size.Then,the value of the surface residual stress after strengthening and the effect of the process parameters on the surface residual stress law were obtained.After strengthening,the value of surface residual compressive stress increased with the increase of jet pressure and abrasive grain size,and the residual stress on the surface of the workpiece was transformed from the residual tensile stress of 34.49 MPa to the residual compressive stress of-129.4 MPa.From the strengthening effect analysis,the surface cracks and tensile stress concentration defects were eliminated,the alloy microstructure was refined,the molten pool structure and spacing changed from the original fish scale shape to the flat shape and the distance between the molten pool was reduced.The surface residual stress values obtained experimentally are compared with those obtained by numerical simulation,the relative error between them is calculated and the maximum error is 5.02%.The feasibility of the results of the established abrasive particle impact strengthening model is proved,and the comprehensive performance of SLM-formed AlSi10Mg alloys with reduced surface defects is improved after strengthening by abrasive water jet.关键词
磨料水射流/SLM成形AlSi10Mg/表面强化/残余应力/表面变形/强化机制Key words
abrasive water jets/SLM-formed AlSi10Mg/surface strengthening/residual stress/surface deformation/strengthening mechanism分类
矿业与冶金
