Life Prediction of Gas Turbine Materials (original) (raw)

Gas Turbine Materials- Current status and its Developmental Prospects-A Critical Review

Advancements made in the field of materials have contributed in a major way in building gas turbine engines with higher power ratings and efficiency levels. Improvements in design of the gas turbine engines over the years have importantly been due to development of materials with enhanced performance levels. Gas turbines have been widely utilised in power generation, industrial sector, marine sector and as aircraft engines. This article focuses on aero engine applications. Advancements in gas turbine materials have been always a major concern – higher their capability to withstand elevated temperature service and more the engine efficiency; for the materials with high temperature to weight ratio helps in weight reduction. The article reviews the evolutionary process that has taken place over the years with reference to the different groups of materials used for aero engines. The review brings out a description of the material grades currently used, prominently including their superior performance characteristics which led to the designer selecting them. A wide spectrum of high performance materials, whose manufacture often involves advanced processing techniques, is used for construction of gas turbines namely special steels, titanium alloys, super alloys. Other major group of materials like ceramics, composites and inter-metallics are presently under intense research and development towards their implementation in various aero-engine components. The present analysis will go into the superior attributes of these various groups making them the designer’s choice for different components in the aero-engine. Many of the components in the aero engines are subjected to fatigue- and /or creep-loading, and the choice of material is then based on the capability of the material to withstand such loads. The paper goes into the types of loading experienced by different components and how advanced gas turbine materials are designed and produced to withstand these loads. Coating technology has become an integral part of manufacture of gas turbine engine components operating at high temperatures, as this is the only way a combination of high level of mechanical properties and excellent resistance to oxidation / hot corrosion resistance could be achieved. The review brings out a detailed analysis of the advanced materials and processes that have come to stay in the production of various components in gas turbine engines.

Failure mechanisms in turbine blades of a gas turbine Engine –an overview

For the past few decades, the gas turbines have been operated at elevated temperatures to have the advantage of achieving higher and higher power output and engine efficiency. The turbine blade is one of the most important components of the gas turbine and is principally made of Nickel base super alloys. Superalloys are metallic materials for service at high temperatures and the excellent thermal stability, tensile and fatigue strengths, resistance to creep and hot corrosion, and micro structural stability possessed by Nickel-base super alloys render the material an optimum choice for application in turbine blades. The main function of turbine blade is to translate thermal energy of gas at high temperature and high pressure into mechanical work. The gas turbine blades operate at very high temperature under conditions of extreme environmental attack and subjected to degradation by oxidation, corrosion and wear etc. Generally, during operation, the turbine blades are subjected to the failure mechanisms like Fatigue, Creep, Corrosion, Erosion and sulphidation etc. The failure of turbine blades may have severe impact on safety and reliability of the gas turbine engine. Keeping this in view, in this paper an attempt has been made to review the blade failure mechanisms and blade failures with some case studies.

Advanced Materials used for different components of Gas Turbine

Design of Turbo machinery is complex and efficiency is directly related to material performance, material selection is of prime importance. Temperature limitations are the most crucial limiting factors to gas turbine efficiencies. The problems at various components are of different magnitudes. As a result, the materials selection for individual components is based on varying criteria in gas turbines. Also materials and alloys for high temperatures application are very costly. This paper is focused on the study of various materials for their applicability for different components of gas turbine for increasing the performance, reliability and emissions in gas turbines. This paper presents a critical review of the existing literature of gas turbine materials. The paper will focus light on above issues and each plays an important role within the Gas Turbine Material literature and ultimately influences on planning and development practices. It is expected that this comprehensive contribution will be very beneficial to everyone involved or interested in Gas Turbines.

Failure analysis and materials development of gas turbine blades

Materials Today: Proceedings, 2020

In the current review, the failure analysis of gas turbine blades and to overcome those failures the development of materials have been discussed. The properties of a gas turbine blades should have exhibit have been reported in the current review. In addition to the above, the importance of coating in gas turbine blade has been listed. After the brief investigation of the failure analysis and materials developed it is observed that still there are some properties to be developed to obtain an optimum gas turbine blade.

Failure analysis of a gas turbine blade made of Inconel 738LC alloy

Engineering Failure Analysis, 2005

The failure analysis of the 70 MW gas turbine first stage blade made of nickel-base alloy Inconel 738LC is presented. The blades experience internal cooling hole cracks in different airfoil sections assisted by a coating and base alloy degradation due to operation at high temperature. A detailed analysis of all elements which had an influence on the failure initiation was carried out, namely: loss of aluminium from coating due to oxidation and coating phases changing; decreasing of alloy ductility and toughness due to carbides precipitation in grain boundaries; degradation of the alloy gamma prime (c 0 ) phase (aging and coarsening); blade airfoil stress level; evidence of intergranular creep crack propagation. It was found that the coating/substrate crack initiation and propagation was driven by a mixed fatigue/creep mechanism. The coating degradation facilitates the crack initiation due to thermal fatigue.

Materials and Component Development for Advanced Turbine Systems

Volume 4: Cycle Innovations; Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Marine

Future hydrogen-fired or oxy-fuel turbines will likely experience an enormous level of thermal and mechanical loading, as turbine inlet temperatures (TIT) approach 1425–1760°C with pressures of 300–625 psig, respectively. Maintaining the structural integrity of future turbine components under these extreme conditions will require durable thermal barrier coatings (TBCs), high temperature creep resistant metal substrates, and effective cooling techniques. While advances in substrate materials have been limited for the past decades, thermal protection of turbine airfoils in future hydrogen-fired and oxy-fuel turbines will rely primarily on collective advances in TBCs and aerothermal cooling. To support the advanced turbine technology development, the National Energy Technology Laboratory (NETL) at the Office of Research and Development (ORD) has initiated a research project effort in collaboration with the University of Pittsburgh (UPitt), and West Virginia University (WVU), working in...