Characterization of LAM-Fabricated Porous Superalloys for Turbine Components

2016 ◽  
Author(s):  
Brandon Ealy ◽  
Luisana Calderon ◽  
Wenping Wang ◽  
Jay Kapat ◽  
Ilya Mingareev ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Porous Structure ◽  
Turbine Blade ◽  
Leading Edge ◽  
Laser Additive Manufacturing ◽  
Internal Impingement ◽  
Edge Segment ◽  
Cycle Efficiency ◽  
Non Destructive

The limits of gas turbine technology are heavily influenced by materials and manufacturing capabilities. Inconel alloys remain the material of choice for most hot gas path components in gas turbines, however recent increases in turbine inlet temperature (TIT) are associated with the development of advanced convective cooling methods and ceramic thermal barrier coatings (TBC). Increasing cycle efficiency and cycle specific work are the primary drivers for increasing TIT. Lately, incremental performance gains responsible for increasing the allowable TIT have been made mainly through innovations in cooling technology, specifically convective cooling schemes. An emerging manufacturing technology may further facilitate the increase of allowable maximum TIT, thereby impacting cycle efficiency capabilities. Laser Additive Manufacturing (LAM) is a promising manufacturing technology that uses lasers to selectively melt powders of metal in a layer-by-layer process to directly manufacture components, paving the way to manufacture designs that are not possible with conventional casting methods. This study investigates manufacturing qualities seen in LAM methods and its ability to successfully produce complex features found in turbine blades. A leading edge segment of a turbine blade, containing both internal and external cooling features, along with an engineered-porous structure is fabricated by laser additive manufacturing of superalloy powders. Various cooling features were incorporated in the design, consisting of internal impingement cooling, internal lattice structures, and external showerhead or transpiration cooling. The internal structure was designed as a lattice of intersecting cylinders in order to mimic that of a porous material. Variance distribution between the design and manufactured leading edge segment are carried out for both internal impingement and external transpiration hole diameters. Through a non-destructive approach, the presented geometry is further analyzed against the departure of the design by utilizing x-ray computed tomography (CT). Employing this non-destructive evaluation (NDE) method, a more thorough analysis of the quality of manufacture is established by revealing the internal structures of the porous region and internal impingement array. Flow testing was performed in order to characterize the uniformity of porous regions and flow characteristics across the entire article for various pressure ratios (PR). Discharge coefficient of internal impingement arrays and porous structure are quantified. The analysis yields quantitative data on the build quality of the LAM process, providing insight as to whether or not it is a viable option for manufacture of micro-features in current turbine blade production.

Characterization of Laser Additive Manufacturing-Fabricated Porous Superalloys for Turbine Components

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Brandon Ealy ◽  
Luisana Calderon ◽  
Wenping Wang ◽  
Ranier Valentin ◽  
Ilya Mingareev ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Inlet Temperature ◽  
Layer By Layer ◽  
Laser Additive Manufacturing ◽  
Internal Impingement ◽  
Edge Segment

The limits of gas turbine technology are heavily influenced by materials and manufacturing capabilities. Lately, incremental performance gains responsible for increasing the allowable turbine inlet temperature (TIT) have been made mainly through innovations in cooling technology, specifically convective cooling schemes. Laser additive manufacturing (LAM) is a promising manufacturing technology that uses lasers to selectively melt powders of metal in a layer-by-layer process to directly manufacture components, paving the way to manufacture designs that are not possible with conventional casting methods. This study investigates manufacturing qualities seen in LAM methods and its ability to successfully produce complex features found in turbine blades. A leading edge segment of a turbine blade, containing both internal and external cooling features, along with an engineered-porous structure is fabricated by laser additive manufacturing of superalloy powders. Through a nondestructive approach, the presented geometry is analyzed against the departure of the design by utilizing X-ray computed tomography (CT). Variance distribution between the design and manufactured leading edge segment are carried out for both internal impingement and external transpiration hole diameters. Flow testing is performed in order to characterize the uniformity of porous regions and flow characteristics across the entire article for various pressure ratios (PR). Discharge coefficients of internal impingement arrays and engineered-porous structures are quantified. The analysis yields quantitative data on the build quality of the LAM process, providing insight as to whether or not it is a viable option for direct manufacture of microfeatures in current turbine blade production.

scholarly journals The Examination of Restrained Joints Created in the Process of Multi-Material FFF Additive Manufacturing Technology

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 903 ◽  
Author(s):  
Janusz Kluczyński ◽  
Lucjan Śnieżek ◽  
Alexander Kravcov ◽  
Krzysztof Grzelak ◽  
Pavel Svoboda ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Three Dimensional ◽  
Acrylonitrile Butadiene Styrene ◽  
Tensile Tests ◽  
Lower Amount ◽  
Internal Quality ◽  
Experimental Production ◽  
Destructive Testing ◽  
Non Destructive

The paper is focused on the examination of the internal quality of joints created in a multi-material additive manufacturing process. The main part of the work focuses on experimental production and non-destructive testing of restrained joints of modified PLA (polylactic acid) and ABS (Acrylonitrile butadiene styrene) three-dimensional (3D)-printed on RepRap 3D device that works on the “open source” principle. The article presents the outcomes of a non-destructive materials test in the form of the data from the Laser Amplified Ultrasonography, microscopic observations of the joints area and tensile tests of the specially designed samples. The samples with designed joints were additively manufactured of two materials: Specially blended PLA (Market name—PLA Tough) and conventionally made ABS. The tests are mainly focused on the determination of the quality of material connection in the joints area. Based on the results obtained, the samples made of two materials were compared in the end to establish which produced material joint is stronger and have a lower amount of defects.

scholarly journals The Examination of Restrained Joints Created in the Process of Multi-material FFF Additive Manufacturing Technology

2020 ◽  
Author(s):  
Janusz Kluczynski ◽  
Lucjan Sniezek ◽  
Alexander Kravcov ◽  
Krzysztof Grzelak ◽  
Pavel Svoboda ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Acrylonitrile Butadiene Styrene ◽  
Tensile Tests ◽  
Lower Amount ◽  
Internal Quality ◽  
Experimental Production ◽  
Destructive Testing ◽  
Non Destructive

The paper is focused on the examination of the internal quality of joints created in a multi-material - additive manufacturing process. The main part of the work focuses on experimental production and non-destructive testing of restrained joints of modified PLA (polylactic acid) and ABS (Acrylonitrile butadiene styrene) 3Dprinted on RepRap 3D device that works on the "open source" principle. The article presents the outcomes of non-destructive materials test in the form of the data from the Laser Amplified Ultrasonography, microscopic observations of the joints area and tensile tests of the specially designed samples. The samples with designed joints were additively manufactured of two materials: specially blended PLA (Market name – PLA Tough) and conventionally made ABS. The tests are mainly focused on the determination of the quality of material connection in the joints area. Based on the results obtained, the samples made of two materials were compared in the end to establish which produced material joint is stronger and have a lower amount of defects.

Adiabatic Film Cooling Effectiveness of a LAM Fabricated Porous Leading Edge Segment of a Turbine Blade

2018 ◽  
Author(s):  
Luisana Calderon ◽  
Andres Curbelo ◽  
Gaurav Gupta ◽  
Jayanta S. Kapat
Keyword(s):  
Additive Manufacturing ◽  
Turbine Blade ◽  
Film Cooling ◽  
Leading Edge ◽  
Metal Powders ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Porous Region ◽  
External Cooling

Laser additive manufacturing (LAM) is an emerging technology that builds parts in a layer-by-layer process by selectively melting metal powders. This additive manufacturing technique among others can produce very complex geometries, which are not possible using conventional methods. A mock segment of the leading edge of a turbine blade, designed with both internal and external cooling features fabricated by LAM of Inconel powder, is investigated. This design consists of an internal impingement cooling array and an engineered-porous structure. This porous region consists of a lattice of intersecting cylinders that simulates the effect of a transpiration cooled segment or permeable wall with a designed porosity of 0.57. Transpiration cooling is a promising external cooling technique capable of reducing thermal gradients at the surface of the blade by providing a more uniform film than conventional discrete film cooling holes. In this current study, adiabatic film cooling effectiveness is experimentally investigated using pressure sensitive paint (PSP) for blowing ratios ranging between 0.03 and 0.15. Using air as the mainstream, and CO2 as the coolant source, a density ratio of 1.5 is obtained. Steady state simulations using RANS are analyzed and used to compare against experimental results. All cases result in an increase in effectiveness values with increasing blowing ratio. Highest effectiveness values are associated with high pressure drop. Coolant uniformity is observed downstream the porous region and mixing becomes more significant as blowing ratio is increased.

scholarly journals Study on Porous Mg-Zn-Zr ZK61 Alloys Produced by Laser Additive Manufacturing

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 635 ◽  
Author(s):  
Min Zhang ◽  
Changjun Chen ◽  
Chang Liu ◽  
Shunquan Wang
Keyword(s):  
Additive Manufacturing ◽  
Surface Morphology ◽  
Laser Energy ◽  
Laser Additive Manufacturing ◽  
Solid Solution Strengthening ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Solution Strengthening ◽  
Precipitated Phases

This study reports the effect of Zn contents on surface morphology, porosity, microstructure and mechanical properties of laser additive manufacturing (LAM) porous ZK61 alloys. The surface morphology and porosity of the LAMed porous ZK61 alloys depend on the laser energy input. With increasing Zn contents, the surface quality of porous Mg-Zn-Zr alloys became worse, the grains are obviously refined and the precipitated phases experienced successive transitions: MgZn → MgZn + Mg7Zn3 → Mg7Zn3. The microhardness was improved significantly and ranged from 57.67 HV to 109.36 HV, which was ascribed to the fine grain strengthening, solid solution strengthening and precipitation strengthening. The LAMed porous Mg-15 wt.% Zn-0.3 wt.% Zr alloy exhibits the highest ultimate compressive strength (73.07 MPa) and elastic modulus (1.785 GPa).

Non-destructive quality control methods in additive manufacturing: a survey

2020 ◽  
Vol 26 (4) ◽  
pp. 777-790 ◽  
Author(s):  
Paschalis Charalampous ◽  
Ioannis Kostavelis ◽  
Dimitrios Tzovaras
Keyword(s):  
Quality Control ◽  
Additive Manufacturing ◽  
Complex Objects ◽  
Destructive Testing ◽  
Content Type ◽  
Wide Range ◽  
Manufacturing Procedure ◽  
Direct Energy ◽  
Non Destructive

Purpose In recent years, additive manufacturing (AM) technology has been acknowledged as an efficient method for producing geometrical complex objects with a wide range of applications. However, dimensional inaccuracies and presence of defects hinder the broad adaption of AM procedures. These factors arouse concerns regarding the quality of the products produced with AM and the utilization of quality control (QC) techniques constitutes a must to further support this emerging technology. This paper aims to assist researchers to obtain a clear sight of what are the trends and what has been inspected so far concerning non-destructive testing (NDT) QC methods in AM. Design/methodology/approach In this paper, a survey on research advances on non-destructive QC procedures used in AM technology has been conducted. The paper is organized as follows: Section 2 discusses the existing NDT methods applied for the examination of the feedstock material, i.e. incoming quality control (IQC). Section 3 outlines the inspection methods for in situ QC, while Section 4 presents the methods of NDT applied after the manufacturing process i.e. outgoing QC methods. In Section 5, statistical QC methods used in AM technologies are documented. Future trends and challenges are included in Section 6 and conclusions are drawn in Section 7. Findings The primary scope of the study is to present the available and reliable NDT methods applied in every AM technology and all stages of the process. Most of the developed techniques so far are concentrated mainly in the inspection of the manufactured part during and post the AM process, compared to prior to the procedure. Moreover, material extrusion, direct energy deposition and powder bed processes are the focal points of the research in NDT methods applied in AM. Originality/value This literature review paper is the first to collect the latest and the most compatible techniques to evaluate the quality of parts produced by the main AM processes prior, during and after the manufacturing procedure.

Development of a Modal-Based Turbomachine Blade-Disk Attachment Inspection Technique

2021 ◽  
Vol 54 ◽  
pp. 147-161
Author(s):  
Khathutshelo Kentridge Mantsha ◽  
Dawood Ahmed Desai ◽  
P. Stephan Heyns
Keyword(s):  
Steam Turbine ◽  
Natural Frequency ◽  
Turbine Blade ◽  
Numerical Models ◽  
Turbine Blades ◽  
Cost Savings ◽  
Leading Edge ◽  
Element Analysis ◽  
Non Destructive ◽  
Attachment Zone

Turbine blade failures are among the leading causes of steam turbine failure. Failure types typically include cracking, rubbing, blade fouling, and foreign object damage. There is currently a range of non-destructive testing methods used to detect damage at the blade-disk attachment zone, all of which involve disassembling of the blade from the disk for periodic inspection. Evidence indicate that a method to detect damage at the blade-disk attachment zone using a non-contact, non-destructive in-situ off-line modal-based structural health monitoring technique could be useful under some circumstances. Such a technique would have the advantage of eliminating the necessity to disassemble blades during inspection. This would result in significant cost savings. Also, defects associated with the disassembly and reassembly of blades would be avoided. Thus, the aim of this study was to develop a modal-based turbomachinery blade disk attachment inspection technique. Modal parameters were acquired from a robust experimental modal analysis of freely supported low-pressure steam turbine blade-disk segment assemblies. Artificial single-location cracks were intentionally introduced into the turbine blades by cutting a 1 mm thickness notch at three probable damage locations, namely, at the upper pinhole on the leading-edge pressure side, above the root at the base of the aerofoil on the leading-edge and on the trailing-edge. In this work, a finite element analysis of the bladed disk segment assemblies was carried out with and without damage. To validate the reliability of the numerical models, the numerical results were correlated with the measured values, the results of which showed a strong correlation. Finally, a parametric study was conducted in which various healthy and damaged blade-disk cases were systematically investigated. This was done to examine the sensitivity of the blade natural frequency to damage. The artificial damage above the root was found to cause the largest changes in natural frequency. These changes were even more pronounced for assemblies with two blades. Receiver operating characteristic curves were used to assess the discriminatory ability of the results. Each damage case was found to be unique and therefore identifiable from its corresponding healthy case.

scholarly journals Diffraction-Based Residual Stress Characterization in Laser Additive Manufacturing of Metals

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1830
Author(s):  
Jakob Schröder ◽  
Alexander Evans ◽  
Tatiana Mishurova ◽  
Alexander Ulbricht ◽  
Maximilian Sprengel ◽  
...  
Keyword(s):  
Residual Stress ◽  
Additive Manufacturing ◽  
Interaction Model ◽  
Research Field ◽  
Laser Additive Manufacturing ◽  
Metal Structures ◽  
Grain Interaction ◽  
Future Demands ◽  
Non Destructive

Laser-based additive manufacturing methods allow the production of complex metal structures within a single manufacturing step. However, the localized heat input and the layer-wise manufacturing manner give rise to large thermal gradients. Therefore, large internal stress (IS) during the process (and consequently residual stress (RS) at the end of production) is generated within the parts. This IS or RS can either lead to distortion or cracking during fabrication or in-service part failure, respectively. With this in view, the knowledge on the magnitude and spatial distribution of RS is important to develop strategies for its mitigation. Specifically, diffraction-based methods allow the spatial resolved determination of RS in a non-destructive fashion. In this review, common diffraction-based methods to determine RS in laser-based additive manufactured parts are presented. In fact, the unique microstructures and textures associated to laser-based additive manufacturing processes pose metrological challenges. Based on the literature review, it is recommended to (a) use mechanically relaxed samples measured in several orientations as appropriate strain-free lattice spacing, instead of powder, (b) consider that an appropriate grain-interaction model to calculate diffraction-elastic constants is both material- and texture-dependent and may differ from the conventionally manufactured variant. Further metrological challenges are critically reviewed and future demands in this research field are discussed.

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