Alloy Selection for Honeycomb Gas Path Seal Systems

Abstract

Metallic honeycombs are widely used in gas turbine engines as inner and outer abradable gas path seals. The ever increasing gas temperatures encountered in the high and low pressure turbine modules of modern engine designs challenge the durability of the thin foil metals used to fabricate seal type honeycomb. In this paper the performance of a number of alloys in turbine seal applications is reviewed. Emphasis is placed on resistance to hot gas corrosion attack and microstructural integrity after exposure to elevated temperatures. The abradability of fabricated seal structures under two distinctly different rub test conditions is reviewed. Among the alloys considered, the Fe-Cr-Al-Y alloy MI 2100 offers a potentially superior combination of oxidation resistance, abradability, fabricability and material cost for seal honeycomb applications.