Tribological Properties of AlSi12-Al2O3 Interpenetrating Composite Layers in Comparison with Unreinforced Matrix Alloy

Abstract

Alumina-Aluminum composites with interpenetrating network structures are a new class of advanced materials with potentially better properties than composites reinforced by particles or fibers. Local casting reinforcement was proposed to take into account problems with the machinability of this type of materials and the shaping of the finished products. The centrifugal infiltration process fabricated composite castings in the form of locally reinforced shafts. The main objective of the research presented in this work was to compare the tribological properties (friction coefficient, wear resistance) of AlSi12/Al 2 O 3 interpenetrating composite layers with unreinforced AlSi12 matrix areas. Profilometric tests enabled both quantitative and qualitative analyses of the wear trace that formed on investigated surfaces. It has been shown that interpenetrating composite layers are characterized by lower and more stable coefficients of friction (µ), as well as higher wear resistance than unreinforced matrix areas. At the present stage, the study confirmed that the tribological properties of the composite layers depend on the spatial structure of the ceramic reinforcement, and primarily the volume and size of alumina foam cells.

Tribological Properties of Single (AlSi7/SiCp, AlSi7/GCsf) and Hybrid (AlSi7/SiCp + GCsf) Composite Layers Formed in Sleeves via Centrifugal Casting

“…The next step is to shape the finished products via high-pressure die casting, squeeze casting, or centrifugal casting. Compared with the unit methods based on powder metallurgy proposed and described by Hekner et al [26,27], centrifugal casting methods are similar to squeeze casting [29], making it possible to obtain a series of near-net shape castings that are also locally reinforced [30]. An example of a practical use of such solutions are locally-reinforced pistons and engine blocks obtained by the high-pressure infiltration of ceramic preforms using liquid Al alloys [31,32].…”

Aluminum Matrix Composite (AlSi7Mg2Sr0.03/SiCp) Pistons Obtained by Mechanical Mixing Method

“…As in other liquid-state processes, the phenomena that determine the permanent matrix bonding and reinforcement in the mechanical mixing method are wetting and reactivity in the molten metal and ceramic reinforcing phase. In the aluminum alloy-SiC system, the modification of alloy composition limits the reaction (formation of Al 4 C 3 ) and improves the wettability in the system [ 13 , 28 , 29 , 30 ].…”

“…While for molding in foundry processes the following are used: gravity sand or die casting, low pressure casting, high pressure die casting, squeeze casting, centrifugal casting, vacuum casting and investment casting. In the case of infiltration of porous preforms mainly the pressure methods are used [ 4 , 11 , 12 , 13 , 14 ].…”

Scratch Testing of AlSi12/SiCp Composite Layer with High Share of Reinforcing Phase Formed in the Centrifugal Casting Process

“…The prepared composite suspension of 10 wt % of SiC p in AlSi12 was cast to graphite forms to obtain a half-product for the subsequent formation of a composite sleeve in the centrifugal casting process. In the next step, composite ingots were melted in a crucible furnace (Figure 3a), which is an integral part of the technological process station MVO500 [38], the design of which enabled tapping the liquid composite suspension directly to a centrifugal mold rotating in the vertical axis system (Figure 3b).…”