scholarly journals Powder Interlayer Bonding of Nickel-Based Superalloys with Dissimilar Chemistries

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2029
Author(s):  
Olivia Stanners ◽  
James Russell ◽  
Sean John ◽  
Helen M. Davies ◽  
Silvia Marchisio
Keyword(s):  
Temperature Gradient ◽  
Elevated Temperatures ◽  
Aerospace Industry ◽  
High Stress ◽  
Compressive Force ◽  
Turbine Engine ◽  
Superior Mechanical Properties ◽  
Interlayer Bonding ◽  
New Generation ◽  
Powder Interlayer

Novel joining methods are crucial for the aerospace industry to repair components damaged in the high stress, high cycle environment of the jet turbine engine. Powder interlayer bonding (PIB) is a novel joining technique that is being explored for use in the aerospace industry. PIB involves the use of a powder interlayer between two faying surfaces alongside a localised temperature gradient and compressive force to produce one joined workpiece. The use of a localised temperature gradient not only reduces the heat affected zone (HAZ) but also reduces the energy requirements for the process as only a small area of the component needs to be elevated in temperature. Nickel-based superalloys are commonly used in the gas turbine engine due to their superior mechanical properties that are maintained even under the most elevated temperatures experienced in the jet turbine engine. It is therefore essential these alloys can be easily repaired. Conventional joining methods such as friction welding have proved difficult for new generation nickel-based superalloys; therefore, there is much interest in PIB as an alternative repair technology. This study shows the potential of PIB to join dissimilar nickel-based superalloys: bonds with very little porosity were observed after only a short processing time.

scholarly journals The Bonding of Additive Manufactured Ti-6Al-4V via the Powder Interlayer Bonding (PIB) Process

2020 ◽  
Vol 321 ◽  
pp. 04041
Author(s):  
P. Davies ◽  
H. Davies ◽  
S. Marchisio
Keyword(s):  
Titanium Alloys ◽  
Fusion Zone ◽  
Aerospace Industry ◽  
Inert Atmosphere ◽  
Tig Welding ◽  
Inert Gas ◽  
Plasma Arc ◽  
High Integrity ◽  
Interlayer Bonding ◽  
Powder Interlayer

Powder interlayer bonding (PIB) is a novel joining technique. The technique has been developed to facilitate high integrity repairs of aerospace components, manufactured from titanium alloys commonly employed in the aerospace industry. The PIB technique utilises an interlayer between the two faying surfaces. In this study heating was supplied via induction, enabling a bond to be created in an inert atmosphere, shielding the fusion zone from oxidation during bonding. The PIB technique proved capable of producing high integrity bonds in additive manufactured Ti-6Al-4V, where approximately 85% of the strength of the alloy is retained after bonding. Advantages of this technique over more established joining methods such as tungsten inert gas (TIG) welding and plasma arc (PA) welding include a narrow fusion zone and localised heating. It is believed that PIB can compete against these more mature techniques, providing a technique suitable for joining a range of alloys found in the aerospace industry.

scholarly journals The Bonding of Additive Manufactured Ti-6Al-4V via the Powder Interlayer Bonding (PIB) Process

2020 ◽  
Vol 321 ◽  
pp. 04022
Author(s):  
P. Davies ◽  
H. Davies ◽  
S. Marchisio
Keyword(s):  
Titanium Alloys ◽  
Fusion Zone ◽  
Aerospace Industry ◽  
Inert Atmosphere ◽  
Tig Welding ◽  
Inert Gas ◽  
Plasma Arc ◽  
High Integrity ◽  
Interlayer Bonding ◽  
Powder Interlayer

Powder interlayer bonding (PIB) is a novel joining technique. The technique has been developed to facilitate high integrity repairs of aerospace components, manufactured from titanium alloys commonly employed in the aerospace industry. The PIB technique utilises an interlayer between the two faying surfaces. In this study heating was supplied via induction, enabling a bond to be created in an inert atmosphere, shielding the fusion zone from oxidation during bonding. The PIB technique proved capable of producing high integrity bonds in additive manufactured Ti-6Al-4V, where approximately 85% of the strength of the alloy is retained after bonding. Advantages of this technique over more established joining methods such as tungsten inert gas (TIG) welding and plasma arc (PA) welding include a narrow fusion zone and localised heating. It is believed that PIB can compete against these more mature techniques, providing a technique suitable for joining a range of alloys found in the aerospace industry.

XD™ Titanium Aluminide Composites

1988 ◽  
Vol 120 ◽  
Author(s):  
L. Christodoulou ◽  
P. A. Parrish ◽  
C. R. Crowe
Keyword(s):  
Titanium Aluminide ◽  
Elevated Temperatures ◽  
Coefficient Of Thermal Expansion ◽  
Measurement Techniques ◽  
Physical Property ◽  
Casting Process ◽  
Matrix Composition ◽  
Al Alloy ◽  
Matrix Composites ◽  
New Generation

AbstractThe advantages of reinforcing metals with ceramic particles to produce metal matrix composites are well known. The behavior of discontinuously reinforced intermetallic compounds, however, has not been extensively studied. Martin Marietta Laboratories has produced a new generation of discontinuously reinforced titanium aluminide composites using a proprietary casting process known as XD™ technology. These new materials possess enhanced properties at room and elevated temperatures and may be cast, extruded, or forged. The effects of matrix composition, reinforcing phase, and thermal mechanical processing on properties have been studied using optical and various electron microscopy and mechanical and physical property measurement techniques to characterize the alloys. To date, most work has been done on a two-phased lamellar Ti-45 a/o Al alloy reinforced with TiB2 ceramic having an equiaxed morphology. Data on temperature dependence of the dynamic Young's modulus, coefficient of thermal expansion, deformation and fracture behavior, and microstructure are presented.

A Coupled Temperature-Displacement Numerical Analysis of Hydraulic Press Workspace

2016 ◽  
Author(s):  
Jakub Jirasko ◽  
Antonin Max ◽  
Radek Kottner
Keyword(s):  
Numerical Analysis ◽  
Computational Model ◽  
Automotive Industry ◽  
Elevated Temperatures ◽  
Compressive Force ◽  
Hydraulic Press ◽  
Metallic Materials ◽  
Pressing Force ◽  
Stress Criterion ◽  
The Press

The analysis is performed on a hydraulic press which is intended for use in the automotive industry and is a part of a production line. The final phase of manufacture of interior and acoustic parts takes place in this press. These interior and acoustic parts are made of sandwich fabric which is inserted into the heated mould of the press and by treatment with a defined pressure (or, more precisely, a defined compression) and temperature, it is formed into its final shape. This press has a frame with four columns and it is not preloaded. Two double acting hydraulic cylinders placed on an upper cross beam exert the compressive force. Due to continuously increasing demands on the accuracy and quality of products not only in the automotive industry, it is necessary to ensure compliance with the accuracy of certain values of machine operation. Especially in this case, the value of accuracy substantially depends on the clamping plates of the press, for which a certain value of flatness is required, both at room temperature and at elevated temperatures. To achieve this accuracy, it is necessary to guarantee sufficient stiffness of the machine to resist the pressing force with the smallest deformation possible. Another crucial factor affecting the accuracy of the machine is heating of the heated clamping plates. Unequal heating of parts of the frame causes additional deformation that has to be quantified and eliminated. The main aim was to verify the design of the press by numerical computation and gather knowledge for modifying the topological design of the press so that it fulfils the required customer parameters of flatness and parallelism for different types of loading. A computational model of the press was created for the numerical solution of a coupled temperature-displacement numerical analysis. The analysis was performed using the finite element method in Abaqus software. The press is symmetrical in two orthogonal planes and the load of the press is considered to be centric. On the basis of these two factors it was possible to carry out the analysis by considering only a quarter of the press. The analysis was used to investigate the effects of static and combined loads from the pressing force and heat on the press. The influence of a cooling circuit located in the press frame for the reduction of frame deformation (and deformation of clamping plates) was investigated. Contacts were defined among individual parts to ensure the computational model had characteristics as close as possible to the real press. The analysis was solved as stationary, on the basis that the cooling of the tool between individual pressing cycles is negligible. The insulating plates are made of a particulate composite material which was considered to have isotropic properties depending on the temperature. For strength evaluation of composite materials all individual components of the stress tensor were examined according to the maximum stress criterion. Hook’s law was considered to be valid for the metallic materials. Von Mises criterion was used to evaluate the strength of the metallic materials. The geometry of the press was discretized using 3D linear thermally coupled brick elements with 8 nodes and full integration (C3D8T). There were approximately 174,000 elements in total. Design procedures for designing a press frame with higher work accuracy (flatness) were proposed with the example of the simplified model of the press table. With these methods it is possible to achieve times higher accuracy than is achieved with conventional method.

scholarly journals Effect of elevated temperature on green gram [Vigna radiata (I).Wilczek] performance under temperature gradient tunnel (TGT) environment in Punjab

2021 ◽  
Vol 23 (1) ◽  
pp. 3-13
Author(s):  
HARPREET SINGH ◽  
PRABHJYOT KAUR ◽  
S.K. BAL ◽  
B.U. CHOUDHURY
Keyword(s):  
Elevated Temperature ◽  
Temperature Gradient ◽  
Grain Yield ◽  
Harvest Index ◽  
Elevated Temperatures ◽  
Ambient Condition ◽  
Green Gram ◽  
Seasonal Temperature ◽  
Early Maturity ◽  
Semi Arid

Physiology of green gram is highly sensitive to fluctuations in the thermal environment. Abnormally high temperatures during pod setting to pod development stage induces reduction in pod setting, nonhealthy development and early maturity of grain which results in yield decline. We evaluated the effect of elevated temperatures in a Temperature Gradient Tunnel (TGT) on phenology, physiology and crop performance of green gram cultivars at semi-arid climate of Indian Punjab (Ludhiana). Five green gram cultivars were grown in TGT chambers in a factorial randomized block design with varying level of elevated temperatures (+3.3° C to 5.2° C) for two consecutive kharif seasons (2015-2016). The results reveal that the phenological stages of green gram, were advanced under elevated temperature within the TGT compared to open / ambient condition by 12-13 days. Maximum influence was observed in pod formationand pod maturity stages. With rise in temperatures by 3.3 to 5.2°C in TGT over ambient condition, the plant height increased but the number of branches per plant and the total above ground biomass as well as grain yield decreased consistently. It was found that with 1 oC increase in average seasonal temperature, the grain yield decreased by 75 kg ha-1. On the other hand, the harvest index was in general lower inside TGT chamber implying adverse influence of elevated temperature on biomass production although the partitioning of biomass was more efficient inside the TGT as evident from increase in harvest index. There was strong negative correlation of elevated temperature (inside TGT) with different yield attributes like 1000 seed weight, number of seeds per pod and number of pods per plant. Among the five green gram cultivars, ML-2037 was the most tolerant while cv. SML-1811 was the most susceptible to elevated temperature condition. In general, the grain yield decreased linearly with gradual increase in temperature.Average seasonal temperature of 29-30 oC may be considered as the favourable thermal conditions for the green gram crop in semi-arid conditions of Punjab. However, the future thrust will be to create more temperature gradients in the lower side so that the critical temperature threshold limits for optimum yield of green gram can be ascertained more accurately.

APPROACHES FOR THE DEVELOPMENT OF FOR AUTOMATED DESIGN AND SIMULATION OF ONBOARD NETWORKS

2021 ◽  
Vol 4 (30) ◽  
pp. 76-86
Author(s):  
V. L. Olenev ◽  
◽  
A. V. Shakhomirov ◽  
Keyword(s):  
Computer Aided Design ◽  
Aerospace Industry ◽  
Automated Design ◽  
Software Product ◽  
Computer Aided ◽  
Aided Design ◽  
New Generation ◽  
New Industry ◽  
Board Networks ◽  
Development Prospects

The article presents an analysis of the development prospects for the aerospace industry in relation to on-board systems and new-generation networks. It also presents the approaches for developing the SANDS software, intended for computer-aided design and simulation of on-board networks. Various approaches are described that will allow the existing software product to be refined and updated to meet new industry demands.

scholarly journals A Small Scale Biomass Fueled Gas Turbine Engine

1998 ◽  
Author(s):  
Joe D. Craig ◽  
Carol R. Purvis
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Small Scale ◽  
Brayton Cycle ◽  
Prime Mover ◽  
Turbine Engine ◽  
Rice Hulls ◽  
Turbine Component ◽  
The Cost ◽  
New Generation

A new generation of small scale (less than 20 MWe) biomass fueled, power plants are being developed based on a gas turbine (Brayton cycle) prime mover. These power plants are expected to increase the efficiency and lower the cost of generating power from fuels such as wood. The new power plants are also expected to economically utilize annual plant growth materials (such as rice hulls, cotton gin trash, nut shells, and various straws, grasses, and animal manures) that are not normally considered as fuel for power plants. This paper summarizes the new power generation concept with emphasis on the engineering challenges presented by the gas turbine component.

Non-Destructive Evaluation of Creep Damage in a Nickel Base Super-Alloy Turbine Bucket

2009 ◽  
Author(s):  
Hector Carreon
Keyword(s):  
Electrical Conductivity ◽  
Eddy Current ◽  
Elevated Temperatures ◽  
Damage Zone ◽  
Creep Damage ◽  
Turbine Engine ◽  
Turbine Component ◽  
Nickel Base ◽  
Turbine Bucket ◽  
Super Alloy

Due to elevated temperatures, excessive stresses and severed corrosion conditions, turbine engine components are subject to creep processes that limit the components life such as a turbine bucket. The failure mechanism of a turbine bucket is related primarily to creep and corrosion and secondarily to thermal fatigue. As a result, it is desirable to assess the current condition of such turbine component. This study uses the eddy current (EC) nondestructive evaluation technique in an effort to monitor the creep damage in a nickel base super-alloy, 7FA stage 2 turbine bucket after service. The experimental results show significative electrical conductivity variations in eddy current images on the creep damage zone of nickel base super-alloy samples cut from a turbine bucket. Thermoelectric power (TEP) measurements were also conducted in order to obtain a direct correlation between the presence of material changes due to creep damage and the electrical conductivity measurements.

Microstructural Characterization of Creep Tested Cryomilled NiAl-13vol. % AlN

1994 ◽  
Vol 350 ◽  
Author(s):  
A. Garg ◽  
J. D. Whittenberger ◽  
B. J. M. Aikin
Keyword(s):  
Steady State ◽  
Compressive Strain ◽  
High Stress ◽  
Microstructural Characterization ◽  
Dislocation Network ◽  
Stress Regime ◽  
Stress Diagram ◽  
Superior Mechanical Properties ◽  
Power Law Creep

AbstractCryomilling of prealloyed NiAl powders, followed by extrusion, has been used to produce a particulate strengthened NiAl-13vol.% AlN material. At 1300 K, the compressive strain rate-flow stress diagram has two distinct deformation regimes, with the transition occurring near 150 MPa. The low and the high stress regimes have power law creep exponents of ∼ 6.1 and 14.2, respectively. Microstructural characterization of the as-extruded and tested samples has been performed to develop an understanding of the superior mechanical properties of the material. The microstructure of the as-extruded material was inhomogeneous and consisted of mantle regions containing a mixture of small NiAl grains (diameter ∼ 50–150 nm) and fine AlN particles (size ∼ 5–50 nm) that surround larger NiAl grains (diameter ∼ 0.3–8.0 μm) which were mostly particle free. In the low-stress regime, samples tested to steady state exhibited a structure composed of subgrain boundaries in the particle-free NiAl grains. In addition, some of the subgrains had developed a well defined dislocation network. AlN patricles occasionally found within large NiAl grains acted as pinning centers for dislocations. Small NiAl grains and the AlN particles constituting the mantle coarsened during these tests. In the high-stress regime, samples tested to steady state exhibited a high density of dislocations in most of the particle-free NiAl grains. Subgrain boundaries were found occasionally but dislocation networks were rare. The AlN particles had not significantly coarsened due to the shorter times at temperature.

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