Preparation And Properties Of Aluminum Matrix Powder Metallurgy Materials

Aluminum powder metallurgy (PM) materials become a hotspot in recent years, it will be commonly used in automotive, aerospace and other fields with the low specific gravity, high specific strength, and the advantages of lightweight. Such materials have been applied in automotive and aerospace industries combined with the near net shape technology of PM process. Aluminum-based PM materials show great potential for the excellent mechanical properties, but there are some restricting factors.Mechanical blending way in material preparation will bring problems of uneven mixture and bad bonding. Moreover, the dense oxide films on the surface of aluminum powders hinder the mutual diffusion of elements which is not beneficial for the improvement of the final PM part. In addition, aluminum is an amphoteric metal, which is sensitive to both the acid and alkaline environments, so the further research on the corrosion resistance of aluminum PM materials is also needed. In recent years, with the development of science and technology, numerical simulation technology has been successfully applied to the powder forming area,which promotes the development of PM technology, it has also become an opportunity to the development of aluminum powder metallurgy materials.In order to preferably study aluminum PM materials, the three following aspects has been carried out:(1)"Copper plating of aluminum powders on strength and hardness of aluminum-copper PM materials": The electroless copper plating is adopted for copper addition, and the sintered aluminum-copper PM bulks were prepared. Scanning electron microscopy (SEM), X-ray diffraction (XRD),and energy dispersive spectrometer (EDS) were used to investigate the properties of the sintered bulks. At the same time, the aluminum-copper sintered bulks were prepared by mechanical blending way for comparison.The results show that the CuAl2 phase with the three-dimensional network structure is generated in the matrix prepared by electroless copper plating way compared with that by mechanical blending way. The formation of such a phase makes the structure more homogeneous and compact which improves the strength and hardness of the materials greatly.(2)"Ni on corrosion resistance of aluminum matrix PM materials":Al-based samples with the nominal compositions of Al94.5-xCu4Mg1.5Nix(X=0, 2, 4, 6, 8 wt.% ) were prepared by the conventional PM process.Scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectrometer (EDS) were used to investigate the properties of the sintered bulks. Electrochemical test and weight loss experiment were carried out to investigate the corrosion resistance. The results show that pitting corrosion occurred in the aluminum matrix immersed in 3.5% NaCl solution and the corrosion resistance of the materials are improved with the addition of Ni.(3)"Powder compacting experiment and numerical simulation":MSC.Marc software was used to simulate the powder compacting process.Simulation under different pressing situations has been carried out to analyze the powder forming law of aluminum based powders. The investigation provides the theoretical basis for the suppressing experiment and provide a reference for simulation research in the field. The results show that MSC.Marc software can undertake the simulation of powder compacting process and obtain powder forming laws in concent with the actual experiment.