PSI - Issue 13

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 1065–1 7 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Int grity Procedia 00 (2018) 000 – 000

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XV Portuguese Conference on Fracture, PCF 2016, 10-12 February 2016, Paço de Arcos, Portugal Thermo-mechanical modeling of a high pressure turbine blade of an airplane gas turbine engine P. Brandão a , V. Infante b , A.M. Deus c * a Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal b IDMEC, Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal c CeFEMA, Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal Abstract During their operation, modern aircraft engine components are subjected to increasingly demanding operating conditions, especially the high pressure turbine (HPT) blades. Such conditions cause these parts to undergo different types of time-dependent degradation, one of which is creep. A model using the finite element method (FEM) was developed, in order to be able to predict the creep behaviour of HPT blades. Flight data records (FDR) for a specific aircraft, provided by a commercial aviation company, were used to obtain thermal and mechanical data for three different flight cycles. In order to create the 3D model needed for the FEM analysis, a HPT blade scrap was scanned, and its chemical composition and material properties were obtained. The data that was gathered was fed into the FEM model and different simulations were run, first with a simplified 3D rectangular block shape, in order to better establish the model, and then with the real 3D mesh obtained from the blade scrap. The overall expected behaviour in terms of displacement was observed, in particular at the trailing edge of the blade. Therefore such a model can be useful in the goal of predicting turbine blade life, given a set of FDR data. ECF22 - Loading and Environmental effects on Structural Integrity Small fatigue crack growth in a high entropy alloy Kai Suzuki a *, Motomichi Koyama b , Hiroshi Noguchi b a Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan b Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan High-entropy alloys (HEAs) contain a large amount of solid solution elements. This implies that the high capability of solid solution strengthening is expected to increase the resistance to fatigue crack growth. Therefore, we investigated the characteristics of microstructurally small fatigue cra k growth of an HEA. In particular, we focus d on microstructural fatigue crack growth behavi r and associated scatter in crack growth rates. In this study, we used an equiatomic Fe-20Cr-20Ni-20Mn-20Co HEA and an Fe-18Cr 14Ni stable austenitic stainless steel. Rotating bending fatigue tests were performed at ambient temperature using smooth round bar specimens. The fatigue limits of the HEA and stainless steel were 250 and 200 MPa, respectively. The higher fatigue limit of the HEA was attributed to the solid solution strengthening. Furthermore, the scatter in crack growth rates of the HEA was more significant than that of the stainless steel owing to the temporal deceleration or non-propagation of the crack. In the stainless steel, as the crack length increased, the scatter in crack growth rates decreased. In contrast, in the HEA, even if the crack length increased, the scatter in crack growth rates remained significant As a factor that is perhaps related to the scatter characteristics, fatigue cracks with a length of approximately 500 µm in the HEA were highly defle ted, compared to those of the stainless st el. © 2018 The Authors. Published by Elsevier B.V. Peer-review und r responsibility of the ECF22 organizers. Keywords: Hig - ntropy alloys; Sm ll fatigue crack growth; Scatter in crack growth rat s. High-entropy alloys (HEAs) are solid solution-strengthened alloys containing four or more elements at an equiatomic or quasi-equiatomic ratio, e.g., Fe-20Cr-20Ni-20Mn-20Co equiatomic alloy (at.%) (Zhang et al., (2014)). Cantor et al. (2004) developed the first HEA, the Fe-20Cr-20Ni-20Mn-20Co HEA, which shows a face-centered cubic (FCC) single-phase structure. This alloy exhibits noticeable mechanical properties such as extraordinary cryogenic © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. ECF22 - Loading and Environmental effects on Structural Integrity Small fatigue crack growth in a high entropy alloy Kai Suzuki a *, Motomichi Koyama b , Hiroshi Noguchi b a Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan b F culty of Engineeri g, Kyushu Univers ty, 744 Motooka, Nishi-ku, F kuoka, 819-0395, Japan Abstract High-entropy alloys (HEAs) contain a large amount of solid solution elements. This implies that the high capability of solid solution strengthening is expected to i crease the resistance t fatigue crack growth. Therefore, we inve tigated the characteristics f microstructurally small fatigue crack growth of an HEA. In particular, we focused on microstructural fatigue crack growth behavi r and associated scatter in crack growth rates. In this study, we used an equiatomic Fe-20Cr-20Ni-20Mn-20Co HEA and an F -18Cr 14Ni stable au tenitic stainless steel. Rotating bending fatig e tests were performed at ambient temperature using smooth round bar specimens. The fatigue limits of the HEA and stainless steel were 250 and 200 MPa, respectively. The higher fatigue limit of the HEA was attributed to the solid solution strengthening. Furthermore, the scatter in crack growth rates of t HEA was more significant than that of the stainless steel owing to the temporal deceleration or non-propag tion f the crack. In the stainles steel, as the k le gt increased, the catt r in crack growth rates decreas d. In c ntrast, in the HEA, even if the crack l ngth increased, the scatter in crack growth rates remained significant As factor th t is perhaps related to the scatter characteristics, fatigue cracks with a length of a p oximately 500 µm in the HEA were highly defl cted, compared to tho of the st i less steel. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of th ECF22 organiz rs. Keywords: High-entropy alloys; Small fatigue crack growth; Scatter in crack growth rates. 1. Introduction High-entropy alloys (HEAs) are solid solution-strengthened alloys containing four or more elements at an equiatomic or quasi-equiatomic ra io, e.g., Fe-20Cr-20Ni-20Mn-20Co equiatomic alloy (at.%) (Zhang et al., (2014)). Cantor et al. (2004) developed the first HEA, the Fe- Cr- Ni-20Mn-20Co HEA, which shows a face-centered cubic (FCC) single-phase structure. This alloy exhibits noticeable mechanical properties such as extraordinary cryogenic © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. Abstract 1. Introduction

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the ECF22 o ganizers. * Corresponding author. Tel.: +81-92-802-7677; fax: +81-92-802-0001. E-mail address: sukaisoccer36@gmail.com * Corresponding author. Tel.: +81-92-802-7677; fax: +81-92-802-0001. E-mail ad ress: sukaisoccer36@gmail.com

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016.

2452-3216  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.224