Cracking in a Gas-Turbine Fan-Duct Assembly Because of Contamination of a Repair Weld
An outer fan-duct assembly of titanium alloy Ti-5Al-2.5Sn (AMS 4910) for a gas-turbine fan section cracked 75 mm (3 in.) circumferentially through a repair weld in an arc weld in the front flange-duct segment. Examination of the crack with a binocular microscope revealed no evidence of fatigue. A blue etch-anodize inspection showed the presence of an alpha case along the edges of the repair weld. The alpha case, a brittle oxide-enriched layer, forms when welds are inadequately shielded from the atmosphere during deposition. The brittleness of this layer caused transgranular cracks to form and propagate in tension under the...
Cracking in a Gas-Turbine Fan-Duct Assembly Because of Contamination of a Repair Weld, ASM Failure Analysis Case Histories: Power Generating Equipment, ASM International, 2019, https://doi.org/10.31399/asm.fach.power.c0047645
Download citation file: