Evaluation of ceramic matrix composite leading edge samples under simulated hypersonic flight conditions

Conference Dates

November 5-9, 2017


Sharp leading edge (LE) samples, with tip radius of curvature of 0.76mm, fabricated from three different Ceramic Matrix Composites CMCs were exposed to simulated hypersonic flight conditions using a direct-connect scramjet rig and their thermal and erosion responses measured. UHTC (20vol%SiC-HfB2) LE samples were used in the same run as controls. The simulated flight conditions approached equivalent free flight conditions of about Mach 7 at 22km altitude, for short durations (~1 min), in combination with prolonged exposure (several minutes to an hour) at Mach 5 flight conditions at the same altitude. All the CMC samples survived the thermal, acoustic and other mechanical shock but exhibited erosion to various extents. In comparison the UHTC samples suffered no significant erosion, but some samples cracked from thermal shock after repeated exposure cycles. The matrix chemistry played a significant role, while the fiber orientation had no significant effect, with damage being dominated by matrix degradation kinetics. A SiC fiber reinforced hybrid UHTC matrix composite leading edge with a 2.5 mm radius of curvature, survived for short duration at Mach 7 condition without significant erosion or cracking.

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