ABSTRACT This paper analyses the effect of turning parameters for Ti-6Al-4 V and Ti-5553, which are generally used in aerospace and industrial applications due to their superior strength to density ratio, corrosion resistance and ability to withstand elevated temperatures. The input variables used in this study are Cutting Speed (CS), Depth of Cut (DoC) and Feed Rate (FR). A three-dimensional machining model is designed in Deform-3D®, an FEM software, to predict results. The output parameters temperature, effective stress, effective strain, and effective strain rate obtained by turning Ti-6Al-4 V & Ti-5553 were analysed based on the input parameters. Taguchi technique and ANOVA were performed for statistical analysis and interpretation of the results. The favourable input values for performing turning operation on Ti-6Al-4 V workpiece with TNMA332_KC90 tool are CS 2000 rpm, Doc 6 mm, FR 0.6 mm/s and with TNMA332 tool are 1750rpm, 2 mm, 0.6 mm/s at high temperatures. Similarly, the optimum input values for Ti-5553 workpieces with TNMA332_KC90 tool are 2000 rpm, 4 mm, 0.9 mm/s and with tool TNMA332 are 150 rpm, 2 mm, 0.3 mm/s. The comparison between coated and uncoated Tungsten Carbide (WC) tools states that optimum values obtained are better in terms of maximum temperature and effective stress, when a coated tool is used rather uncoated, for both workpieces.

Analysis on behavior of Ti-6al-4v & Ti-5553 by performing turning operation using deform-3d

A Critical Review on Gas Turbine Cooling Performance and Failure Analysis of Turbine Blades

Vibration fatigue characteristics are critical for rotating machinery components such as turbine rotor blades. Lattice structures are gaining popularity in engineering applications due to their unique ability to reduce weight and improve the mechanical properties. This study is an experimental investigation of octet-truss lattice structure utilization in turbine rotor blades for weight reduction and to improve vibration fatigue characteristics. One completely solid and three lattice infilled blades with variable strut thickness were manufactured via additive manufacturing. Both free and forced experimental vibration analyses were performed on the blades to investigate their modal and vibration fatigue characteristics. The blades were subjected to random vibration using a vibration shaker. The response was measured using a triaxial accelerometer in terms of vibration acceleration time histories in the X, Y, and Z directions. Results indicate a weight reduction of up to 24.91% and enhancement in the first natural frequency of up to 5.29% were achieved using lattice infilled blades. The fatigue life of the blades was investigated using three frequency domain approaches, namely, Lalanne, Dirlik and narrow band. The fatigue life results indicate that the 0.25 mm lattice blade exhibits the highest fatigue life, while the solid blade exhibits the lowest fatigue life of all four blades. The fatigue life of the 0.25 mm lattice blade was 1822-, 1802-, and 1819- fold higher compared to that of the solid blade, using the Lalanne, Dirlik, and narrow-band approaches, respectively. These results can serve as the first step towards the utilization of lattice structures in turbine blades, with thermal analysis as the next step. Therefore, apart from being light weight, the octet-truss lattice infilled blades exhibited superior vibration fatigue characteristics to vibration loads, thereby making them a potential replacement for solid blades in turbine rotors.

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Vibration-Based Fatigue Analysis of Octet-Truss Lattice Infill Blades for Utilization in Turbine Rotors

An aluminized coating can improve the high-temperature oxidation resistance of turbine blades, but the inter-diffusion of elements renders the coating’s thickness difficult to achieve in non-destructive testing. As a typical method for coating thickness inspection, X-ray fluorescence mainly includes the fundamental parameter method and the empirical coefficient method. The fundamental parameter method has low accuracy for such complex coatings, while it is difficult to provide sufficient reference samples for the empirical coefficient method. To achieve accurate non-destructive testing of aluminized coating thickness, we analyzed the coating system of aluminized blades, simulated the spectra of reference samples using the open-source software XMI-MSIM, established the mapping between elemental spectral intensity and coating thickness based on partial least squares and back-propagation neural networks, and validated the model with actual samples. The experimental results show that the model’s prediction error based on the back-propagation neural network is 4.45% for the Al-rich layer and 16.89% for the Al-poor layer. Therefore, the model is more suitable for predicting aluminized coating thickness. Furthermore, the Monte Carlo simulation method can provide a new way of thinking for materials that have difficulty in fabricating reference samples.

https://www.mdpi.com/2079-6412/12/6/764/pdf?version=1654168379

Prediction Model of Aluminized Coating Thicknesses Based on Monte Carlo Simulation by X-ray Fluorescence

Aiming at the fatigue life failure of a gas turbine blade, an optimization design of the blade was performed based on the test phenomenon and results of fatigue life analysis. As a result, the stress of the blade is decreased, and the fatigue life of the blade is increased.

https://doi.org/10.1088/1742-6596/2252/1/012025

Structure Design and Optimization of a gas turbine blade

Comparison and selection of suitable materials applicable for gas turbine blades

Studies on the selection of cutting parameters of Ti-6Al-4V alloy turning operation using principal component analysis

Nickel based superalloys are of a typical class of materials with an exceptional capability of retaining strength and toughness at high temperatures. Also, they have high resistance to degradation in corrosive environments. These properties of superalloys make them ideal materials for gas turbine engines used in power generation, marine engineering and aircraft applications. Earlier, researchers studied about the suitability of cast and wrought superalloys for their applicability in gas turbines. Superalloys are developed from polycrystalline to directionally solidified alloys and finally single crystal alloys by investment casting process for making turbine blade. In this work, the powder metallurgy technique is analysed for determining its appropriateness for making nickel based superalloys in gas turbines. This technique includes powder blending, compaction and sintering with or without post heat treatment for making a product. This process can offer high performance applications, where unique microstructural and mechanical characteristics are required. Refractory material can be easily alloyed by this technique, to enhance heat bearing capabilities. In this work, the development of nickel based superalloys by powder metallurgy technique, their composition as well as the influence of various elements on mechanical properties is analysed. Major defects like prior particle boundary (PPB) precipitation, thermally induced porosity (TIP), and non-metallic inclusion have to be taken care, in order to see that the mechanical properties are not deteriorated. It is observed that alloys like IN100, Rene95, and N18, Rene 88DT, ME3 and R1000 developed by powder metallurgy technique have sufficient temperature bearing capability for 1000 hr service life at 630 MPa. Alloys like U720 Li, IN 718 plus and U 720, made by casting technique and alloys like ME3, IN 100, and U720, made by powder metallurgy technique are compared on the basis of stress and temperature bearing capability. It is found that ME3 alloy prepared by powder metallurgy technique is the efficient nickel based superalloy with maximum heat bearing capability.

Geetika k. Salwan

Papers

Comparison and selection of suitable materials applicable for gas turbine blades

Studies on the selection of cutting parameters of Ti-6Al-4V alloy turning operation using principal component analysis

Analysis on the Suitability of Powder Metallurgy Technique for Making Nickel Based Superalloys

Investigation on compaction pressure and sintering temperature suitable for Nimonic 90 superalloy