Structure Investigation of Ball Milled Composite Powder Based on AlSi5Cu2 Alloy Chips Modified by Sic Particles

Abstract

The paper is focused on the processing of aluminum alloy chips using powder metallurgy. Chips obtained from recycled AlSi5Cu2 alloy were ball milled with the addition of silicon carbide powder with an average size of 2µm. Mechanical alloying process was employed to obtain homogeneous composite powder. The effect of processing time (0 -40h) on the homogeneity of the system was evaluated, as well as a detailed study of the microstructure of AlSi5Cu2 aluminum chips and SiC particles during MA was carried out. Addition of silicon carbide (10, 20wt%) to recycled aluminium chips and application of MA lead to fragmentation of the homogeneous composite powder down to particle size of about 3µm and spheroidization. The addition of hard SiC particles caused reinforcement and reduced the milling time. Higher content of silicon carbide and longer processing time allowed to obtain AlSi5Cu2/SiC powders with microhardness ∼500HV 0.025 . The results of MA were investigated with SEM, EDS, LOM, XRD and showed that relatively homogeneous distribution of SiC reinforcements in the matrix as well as grain refinement of aluminum solid solution down to 50nm can be obtained after 40h of processing.Keywords: AlSiCu alloy chips, Recycling, Powder metallurgy, Mechanical alloying, Al-SiC composite powder W artykule przedstawiono metodę otrzymywania proszku kompozytowego na osnowie wiór stopu aluminium AlSi5Cu2 pochodzących z recyklingu z dodatkiem węglika krzemu (SiC-α, 2µm). Określono wpływ czasu mielenia oraz dodatku SiC na mikrostrukturę i właściwości proszku kompozytowego. Dodatek SiC (10, 20%mas) do wiór stopu aluminium i zastosowanie mechanicznej syntezy pozwala na otrzymanie jednorodnego i drobnoziarnistego proszku o wielkości 3µm i kształcie zbliżonym do sferycznego. Dodatek twardych cząstek SiC powoduje umocnienie proszku oraz skrócenie czasu mielenia. Dodatek SiC i zastosowanie 40h mielenia pozwala otrzymać cząstki proszku o mikrotwardości około 500 HV 0,025 .Badania proszku kompozytowego przeprowadzone na mikroskopie optycznym, SEM oraz TEM potwierdziły jednorodne rozmieszczenie cząstek SiC w osnowie oraz zmniejszenie wielkości ziarna do 50nm po 40 godzinach procesu.

An Experimental Study Of Aluminum Alloy Matrix Composite Reinforced SiC Made By Hot Pressing Method

“…After mechanical alloying composite powder displaying a fine, homogeneous distribution of the reinforcement within the particle (Fig. 4) what was in detail demonstrated in previous work [15][16]. [17] Applied parameters of mechanical alloying of AlSi5Cu2 chips and SiC leads to obtain composite powder where the SiC particles are apparently occluded by Al (Fig.…”

“…To minimize the extreme cold welding and prevent high temperature, the process was stopped periodically (45min) after each 15 min of milling. Detailed results of the composite powder preparation and properties have been reported in [14][15][16]. The prepared and identified powder mixtures were finally densified by the hot pressing method in a specially constructed chamber.…”

Influence of Milling Time on the Crystallite Size of AlSi5Cu2/SiC Composite Powder

“…To minimize the extreme cold welding and prevent high temperature, the process was stopped periodically for 45 min after each 15 min of milling. Detailed results of the composite powder preparation and properties have been reported in [11][12][13][14].…”

Spark Plasma Sintering of Low Alloy Steel Modified with Silicon Carbide

“…On the other hand, if the sintering process is carried out improperly, the addition of silicon carbide may decrease impact strength and elongation, and it may significantly reduce wear resistance of sintered materials. The SPS method is a short time consolidation technique (the sintering time is shorter than in the conventional PM process and heating/cooling rates are higher), which also allows for synthesis of various materials (metals, ceramics and composites) [15][16][17][18][19][20]. Moreover, with the use of the SPS it is possible to obtain materials with a porosity below 1% which significantly increases corrosion resistance and mechanical properties.…”