Fatigue in gas turbine components

Abstract

Life of hot section components of gas turbine performs at the limiting condition of exposure when thermal barrier coating (TBC) is applied. Insulation and resistance to high temperature corrosion rise efficiency of engines. TBC is applied in various forms in different sectors, which included thick TBC, thin TBC, and duplex/triples/ multilayered coatings of ceramics and metal compositions. Bond coat (BC) and topcoat (TC) composition and treatment processes are exploited for optimum failure free design. However combined HCF-LCF performances at high temperature reduce life. Mismatch reversal of relative stresses often has been used to be variable for optimization. In cases of prolonged trouble free exposure in service, the atmos-pheric contaminant appears to be damaging. These include wear of grit and dust, attack of reaction products of fuel, and formation of SiO2-FexOy composed ceramic sinters in place of ceramic insulation coatings. Fatigue is reviewed in this paper to study characteristics of materials of various turbine components at high temper-ature. Effects of temperature of exposure in different instances are to produce damage mechanisms and requirement of different preventive attention.