Fig. 8 Two shipboard turbine blades. Pressure side shown facing out of the page. Arrows denote areas where heavy corrosion products are observed. More

Fig. 11 Microstructures of nickel-base Alloy 713C turbine blades. (a) Original structure prior to service. (b) Coarsening of γ' precipitates and elimination of secondary γ' caused by 5000 h of service More

Fig. 3 The evolution of the processing of nickel-base superalloy turbine blades. (a) From left, equiaxed, directionally solidified, and single-crystal blades. (b) An exposed view of the internal cooling passages of an aircraft turbine blade. Source: Ref 5 More

Fig. 1 Macrostructure of three turbine blades: polycrystalline (left), columnar grain directionally solidified (center), and single-crystal directionally solidified (right) More

Fig. 11 Hot corrosion attack of René 77 nickel-base alloy turbine blades. (a) Land-based, first-stage turbine blade. Notice deposit buildup, flaking, and splitting of leading edge. (b) Stationary vanes. (c) A land-based, first-stage gas turbine blade that had type 2 hot corrosion attack. (d More

Fig. 12 Heat-damaged turbine blades. (a) Heat-damaged first- or second-stage turbine blade (A), which remained intact but with a darkened appearance. It is common to have blades that appear to be in relatively good condition but with an underlying overtemperature condition. (b) Two third-stage More

Fig. 13 Flow diagram for remaining life assessment of gas turbine blades More

Fig. 14 Sectioning of turbine blades for metallographic examination. (a) Typical locations for cross sectioning of turbine blades. (b) View of Sectioned blade More

Fig. 28 (a) Photograph of fourth-stage turbine blades prior to removal. The first blade to fail is indicated with an arrow; an exhaust thermocouple is shown in the foreground. (b) Photograph of blade fracture surface after sectioning. Note the blue discoloration at the trailing edge. (c More

Fig. 12 (a) Photograph showing one of the intact steam turbine blades from the failed stage. The arrow indicates the fracture location. (b) Photograph of the fracture surface. Scale: millimeters. (c) Scanning electron fractograph of the initiation region showing a mixed transgranular More

Fig. 4 Failed second-stage turbine blade. (a) Photograph of failed blade, with fracture at the top of the image. (b) Stereomicroscopic image of fracture surface showing coarse, intergranular topology. (c) Scanning electron fractograph showing void coalescence on fracture surface. (d) Optical More

Fig. 15 Cermet turbine blade infiltration mold assembly. Source: Ref 19 More

Fig. 23 (a) In the original design of this investment cast turbine blade, careful removal of the gates located on the contoured surface was required, to maintain the airfoil shape. (b) Simplified gating and gate removal were made possible by eliminating one notch and gating into a flat surface More

Fig. 27 High-temperature oxidation of the tip of an industrial gas turbine blade. Below the tip, a coating is protecting the base metal. See the article “Corrosion of Industrial Gas Turbines” in this Volume. More

Fig. 28 Severe attack of an aeroderivative gas turbine blade by hot corrosion. See the article “Corrosion of Industrial Gas Turbines” in this Volume. More

Fig. 10 Close-up of failed turbine blade. Cracking has initiated at platform/stem transition where corrosion has occurred. Original magnification 20× More

Fig. 11 Crack propagation direction of failed turbine blade. Corrosion propagates over 60% of the stem wall, thus increasing the applied stresses in the remaining stem wall. Fracture shows a sharp transgranular characteristic suggesting cleavage or high cycle fatigue. Original magnification 55× More

Fig. 9 Tip cracking of a directionally solidified MAR-M-246 turbine blade More

Fig. 5 Severe attack of an aeroderivative gas turbine blade by hot corrosion More

Fig. 26 Strain/temperature history on a turbine blade. Source: Ref 118 More