Sliding wear performance of Al–Co alloys fabricated by vacuum arc melting and correlation with their microstructure

A Critical Review on Al-Co Alloys: Fabrication Routes, Microstructural Evolution and Properties

“…The main features that have been reported in this vast range of Co contents (2-20 wt % Co) include eutectic morphology for the lower compositions, directional growth, brick-like mode of growth and side brunching. For 2-5 wt % Co, a dual fibrous eutectic microconstituent with a lamellar eutectic microconstituent has been reported [35]. Similar microstructural outcomes have been reported in vacuum arc melted Al-Co alloys (1.1-6.3 wt % Co).…”

“…This has been attributed to the increasing volume fraction of the hard Al 9 Co 2 intermetallic phase with increasing Co content [69]. The hardness of Al-Co alloys increases with increasing Co content, which is attributed to the increase in the volume fraction of Al 9 Co 2 and increasing Co dissolved within the Al matrix [35,76]. Several works focused on Al-Co alloys with different cobalt additions, from 2 wt % Co up to 20 wt % Co, in the hypereutectic region using vacuum arc melting [76,78].…”

“…The effect of Al 9 Co 2 in the sliding wear performance (AISI 52100 steel counter body) of Al-Co alloys in a wide range of compositions (2-20 wt % Co) has been the focus of a recent work (Figure 6) [35]. According to the results, the wear rate of Al-Co alloys decreases with increasing Co content due to increasing volume fraction of Al 9 Co 2 intermetallics from 19 vol % (Al-2 wt %Co) to 63 vol % (Al-20 wt % Co).…”

“…The beneficial action of Al 9 Co 2 in strengthening the Al matrix can be attributed to another factor: the matrix-particle bond. In this case, the Al 9 Co 2 intermetallic is formed in situ, and therefore, the Al-Al 9 Co 2 interface bond is strong, which is beneficial to achieve high wear resistance [35]. Increasing additions of Co results in a higher volume fraction of Al 9 Co 2 and therefore in a reduction in the Al matrix surface area, thus leading to a reduction in possible paths for plastic deformation [90][91][92].…”

“…During the last decade, the focus shifted on the fabrication of bulk Al-Co alloys, using non-equilibrium techniques such as vacuum arc melting, and the assessment of their surface degradation properties. The effect of the fabrication method and composition on the microstructure and properties has been the focus of several works [34,35]. In another recent work, the use of Al-Co intermetallics as ex situ reinforcement in Al-based composites has been studied, highlighting the versatility of the material [36].…”