Experiments And Mesoscopic Scale Simulation Of 2024 Aluminum Alloy Powder Hot-embossed Forming

In recent years,powder forming technology has become more and more important in the industrial development.The earliest powder forming technology used in the preparation of metal and metal matrix composites is powder metallurgy.With the development of modern science and technology,the method of metal powder warm pressing,which integrates near net forming,energy saving and high efficiency,has gradually developed into a high-tech forming method with low cost,high efficiency and high performance.Powder warm forming technology widely used,but about the numerical simulation of temperature,pressure molding powder at present most of the powder as a continuum of compressible processing,using porous Shima ellipsoid yield criterion or geotechnical learn Drucker Prager/Cap yield criterion,not the powder particles discretization for such powder particles in the warm forming process can't intuitive reflect the deformation,stress and flow,and so on and so forth.In this paper,the sintering equipment was used to prepare aluminum alloy powder warm-pressed specimens,and the influence of temperature and holding time on the density of the powder warm-pressed specimens was analyzed.The results show that when the pressing force is set to 2k N,the compactness of the sample is higher with the temperature rising.The axial shrinkage rate of the sample at 300? is 22%,and it reaches 40% at 450?.However,when other conditions are fixed,holding time has little effect on the compactness of the sample.Then thermal simulation experiments were carried out to obtain the true stress-true strain curves under different thermal deformation conditions,and the plastic constitutive equation of aluminum alloy powder under high temperature was obtained by linear regression method.The discrete element software Edem was used to establish the powder model,which was introduced into the finite element software Abaqus through secondary development.The influence of force and deformation of powder particles at different positions in the process of powder warm pressing was analyzed.At the same time,the influence of different temperature,different pressing force and different friction coefficient parameters on powder warm compaction was analyzed.Finally,the powder model was imported into the Fluent software,and the temperature was raised to the semi-solid temperature to observe the melting and flow of the powder particles at the semi-solid temperature.