Development and Characterization of Functionally Gradient Al–Si Alloy Using Cast-Decant-Cast Process

Abstract

A cylindrical component of functionally gradient Al alloy with high silicon in the outer and low silicon in the core was produced using cast-decant-cast (CDC) process. The preparation of the component consisted of pouring high Si-Al alloy first into a cylindrical mould, decantation of un-solidified liquid after the alloy solidified for a desired thickness against the mould walls and subsequently pouring the low Si-Al alloy at superheated temperature, so that the first alloy got partially re-melted forming a functionally gradient material (FGM) region between the two. The characteristics of FGM region like depth, size, shape and distribution of Si particles in the cross section of CDC alloy were evaluated by optical microscopy. Hardness tests and sliding pin-on-disc wear tests were carried out to compare hardness and wear resistance of outer, FGM and core regions. The micrographs of wear surfaces showed that the FGM region has better wear resistance as compared to outer and core regions as seen from the decreased delamination of wear tracks.

Recent Trends in Casting Technology of Functionally Graded Metallic Alloys

“…Then, the remaining un-solidified molten of the first alloy is decanted, and the second alloy is poured into the mold. Anandavel B. et al [102] used the CDC method to study the production as well as characterization of FGM of Al-Si alloys. The CDC method made a cylindrical component of functionally gradient Al alloy with high silicon on the outside and low silicon in the center.…”