Effect of Structure on Creep Behaviour of Superalloy Single Crystals

2005 ◽  
Vol 482 ◽  
pp. 267-270
Author(s):  
Petr Lukáš ◽  
Ludvík Kunz ◽  
Milan Svoboda ◽  
J. Čadek
Keyword(s):  
Chemical Composition ◽  
Creep Rate ◽  
Single Crystals ◽  
Turbine Blade ◽  
Applied Stress ◽  
Low Cost ◽  
Creep Behaviour ◽  
Time To Failure ◽  
Dislocation Sources ◽  
Effect Of Structure

Creep behaviour of two types of superalloy single crystals of the orientation <001> was studied at 850 °C in air to assess their relative suitability for turbine blade applications: CMSX-4 and its potential low cost alternative, CM186LC. The chemical composition of these two superalloys is similar, their microstructure, especially g/g’ distribution, differs substantially. At the same applied stress, the time to failure of CM186LC is shorter than that of CMSX-4. Simultaneously, the creep rate of CM186LC is higher than that of CMSX-4 for the whole lifetime. This is attributed to easier activation of dislocation sources within large g’particles present in CM186LC crystals.

scholarly journals Effect of Low-Temperature Annealing on Creep Properties of AlSi10Mg Alloy Produced by Additive Manufacturing: Experiments and Modeling

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 179
Author(s):  
Chiara Paoletti ◽  
Emanuela Cerri ◽  
Emanuele Ghio ◽  
Eleonora Santecchia ◽  
Marcello Cabibbo ◽  
...  
Keyword(s):  
Creep Rate ◽  
Applied Stress ◽  
Minimum Creep Rate ◽  
Annealing Treatment ◽  
Constant Load ◽  
Experimental Conditions ◽  
Creep Properties ◽  
Low Temperature Annealing ◽  
Physically Based ◽  
Excellent Description

The effects of postprocessing annealing at 225 °C for 2 h on the creep properties of AlSi10Mg alloy were investigated through constant load experiments carried out at 150 °C, 175 °C and 225 °C. In the range of the experimental conditions here considered, the annealing treatment resulted in an increase in minimum creep rate for a given stress. The reduction in creep strength was higher at the lowest temperature, while the effect progressively vanished as temperature increased and/or applied stress decreased. The minimum creep rate dependence on applied stress was modeled using a physically-based model which took into account the ripening of Si particles at high temperature and which had been previously applied to the as-deposited alloy. The model was successfully validated, since it gave an excellent description of the experimental data.

Interfacial interactions between urea formaldehyde and cellulose nanofibrils (CNFs) of varying chemical composition and their impact on particle boards manufacture (PBs)

2021 ◽  
Author(s):  
Maria C. Iglesias ◽  
Philip S. McMichael ◽  
Osei A. Asafu-Adjaye ◽  
Brian K. Via ◽  
Maria S. Peresin
Keyword(s):  
Chemical Composition ◽  
Building Materials ◽  
Colloidal Stability ◽  
Low Cost ◽  
Urea Formaldehyde ◽  
Cellulose Nanofibrils ◽  
Global Market ◽  
Modulus Of Rupture ◽  
Superior Performance ◽  
Interfacial Interactions

Abstract Wood-based panels are commonly used as building materials for interior and exterior purposes. Their production and utilization have increased over the past decades due to the useful properties they present. Adhesive-bonded products make up to 80% of the wood alternatives on the global market, and of that, urea-formaldehyde (UF) makes up approximately 81% of the resins used. Formaldehyde-based resins are used due to their effectiveness and low cost, as well as their ease of application and lack of color. Nevertheless, their main disadvantages are the lack of tackiness and the emission of formaldehyde over time. To improve UF performance, the utilization of microfibrillated cellulose, has been demonstrated to be effective. However, more understanding on the mechanisms of the interactions is of relevant importance. In this work, we studied interfacial interactions between UF with bleached (BCNF) and unbleached (LCNF) cellulose nanofibrils using Quartz Crystal Microbalance with dissipation monitoring (QCM-D) technique observing the superior performance of lignin-containing CNF. Additionally, the surface free energies were investigated using Contact Angle Measurements (CA) showing a decrease of the values mainly when utilizing LCNF, which was later correlated with the wettability properties of the particle boards (PBs). PBs with different adhesive/CNF formulations were produced showing larger improvements when adding LCNF in terms of modulus of elasticity (MOE), modulus of rupture (MOR), and internal bonding (IB). To gain a better understanding on the interactions between CNF and UF, CNF was fully characterized in terms of morphology, chemical composition, charge density, as well as thermal and colloidal stability.

Life Prediction of Directionally Solidified Air Cooled HPT Gas Turbine Blade Used in a Supersonic Aircraft Using FEM

2013 ◽  
Author(s):  
S. Esakki Muthu ◽  
S. Dileep ◽  
S. Saji Kumar ◽  
D. K. Girish
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Operating Conditions ◽  
Test Facility ◽  
Time To Failure ◽  
Generation Process ◽  
Gas Turbine Blade ◽  
Directionally Solidified ◽  
Life Estimation ◽  
Supersonic Aircraft

Life estimation of Directionally Solidified (DS) MARM-247 HPT gas turbine blade used in a turbofan engine of a supersonic aircraft is presented. These blades were drafted into the engine as a replacement for the polycrystal (NIMONIC) blades since a more efficient, reliable and durable material with high strength and temperature resistance was required to further enhance the life of the turbine blade and the efficiency of the power generation process. The supersonic aircraft is having a repeated mission cycle of a fast acceleration from idle, a 1hr cruise at Mach 1.5 and a fast deceleration to idle. The mission cycle which is a repetition of acceleration, cruise and deceleration cycles can produce wide variety of complex loading conditions which can result in HCF, LCF and creep damage of the turbine blade. Empirical equation of the universal slope developed by Manson was used to estimate the damage component due to LCF. The cumulative stresses and strains due to creep as a function of time was determined using Time hardening rule. Creep data for MARM-247 was correlated using LMP to predict the lives to 1% of creep strain at worst possible combination of temperature and stress value. Damage due to creep per mission cycle was determined using Life fraction Rule proposed by Robinson and Taira. The vibration characteristics of the turbine blade were predicted using Modal analysis. Campbell diagram was plotted to ascertain whether any nozzle passing frequency fall within the working range of the blade. Harmonic analysis was carried out to evaluate the magnitude of the alternating stresses resulting from the blade vibrations at resonance during the acceleration and deceleration cycle. HCF life of the turbine blade was assessed using Goodman diagram. The total damage of the turbine blade per mission cycle due to the above loading was assumed as the combination of the individual damage due to fatigue and creep. Time to failure under combined creep and fatigue damage was estimated using linear damage rule. Non linear features of FEA tool ANSYS12.0 was exploited to calculate the stress distribution, creep, plastic and the total strain encountered by the turbine blade as a function of mission cycle time. The loading spectrum associated with the mission cycle which includes the temperature, gas pressure and the speed profiles were obtained from a sophisticated engine ground test facility which was configured to simulate actual engine operating conditions. The proposed method of cyclic life estimation using FEM was validated by performing various component and engine level tests. A good agreement was observed between the calculated and observed blade lives.

scholarly journals Cereal bar with cassava bagasse: chemical composition and sensory acceptance

2016 ◽  
Vol 7 (2) ◽  
pp. 42
Author(s):  
Aparecida De Fátima Oliveira Silva ◽  
Leila Maria Girondi ◽  
Suellen Jensen Klososki ◽  
Tatiana Colombo Pimentel ◽  
Carlos Eduardo Barão
Keyword(s):  
Chemical Composition ◽  
Low Cost ◽  
Good Alternative ◽  
Production Costs ◽  
Raw Material ◽  
Brazil Nuts ◽  
Sensory Acceptance ◽  
Cassava Bagasse ◽  
Hedonic Scale ◽  
Cereal Bars

Cassava bagasse, regarded as an agricultural residue can be used as raw material in the development of new products. Cereal bars are foods that have increasingly gained consumers because of the practical use. The objective of this study was to evaluate the effect of adding cassava bagasse (0, 8 and 25%) on the chemical composition and sensory acceptance of coconut cereal bars with Brazil nuts. Cereal bars with cassava bagasse had higher moisture, protein and carbohydrates (fiber) contents than cereal bars without bagasse, lower ash contents and similar fat content. The addition of cassava bagasse caused a decrease in the acceptance of the cereal bars only in the concentration of 25%, however, the products had hedonic values greater than 7 in a 9-point hedonic scale and acceptability indices higher than 80%, indicating that consumers moderately liked them. It can be concluded that the use of up to 25% cassava bagasse in the cereal bar formulation yields products with improved nutritional value and appropriated consumer acceptance. The addition of cassava bagasse to food products is a good alternative in the use of this byproduct, due to the sensory characteristics of the obtained products and the reduction of production costs, because the cassava bagasse has low cost and increases the production yield.

Analytical Processing Development of Tin Element Using Wavelength Dispersion X-Ray Fluorescence (WDXRF) Technique

2018 ◽  
Vol 879 ◽  
pp. 201-205 ◽  
Author(s):  
Nisakorn Nuamsrinuan ◽  
Weeranuch Kaewwiset ◽  
Pichet Limsuwan ◽  
Kittisakchai Naemchanthara
Keyword(s):  
Neutron Activation Analysis ◽  
Chemical Composition ◽  
Activation Analysis ◽  
Tin Oxide ◽  
Low Cost ◽  
Percentage Error ◽  
Sample Weight ◽  
X Ray ◽  
Naa Technique ◽  
Analytical Processing

The aim of this work was to develop technical analysis of wavelength dispersion X-ray fluorescence (WDXRF) and compare with technical neutron activation analysis (NAA). First, the standard of tin oxide (SnO) was ground into powder and mixed with boric acid (H3BO3) as binder at different weight. All of samples were investigated by WDXRF in normalize mode.The results indicated that the range can use to calibration at sample weight 0.2, 0.3 and 0.4 g. Next, the three SnO samples from different area (A, B and C) were ground, mixed with binder at ratio 0.2, 0.3 and 0.4 g and investigated by WDXRF in normalize mode. The results show tin (Sn) content of sample area A, B and C were 75.71, 74.61 and 71.01%, respectively. The result from NAA technique show Sn content of sample A, B and C were 79.36, 77.48 and 73.35%. The percentage error of WDXRF and NAA technique of the samples from the different area had 4.63, 3.70 and 3.19%. From the experiment as examined that the WDXRF technique could be improve process for determine chemical composition which one of choice for easy to used and low cost.

Calorimetry, chemical composition and in vitro digestibility of sugarcane treated with calcium hydroxide

2018 ◽  
Vol 69 (4) ◽  
pp. 406
Author(s):  
Alexandre M. Dias ◽  
Luís C. V. Ítavo ◽  
Júlio C. Damasceno ◽  
Camila C. B. F. Ítavo ◽  
Geraldo T. Santos ◽  
...  
Keyword(s):  
Weight Loss ◽  
Chemical Composition ◽  
Calcium Hydroxide ◽  
Nutritive Value ◽  
Low Cost ◽  
Alkaline Treatment ◽  
In Vitro Digestibility ◽  
Cellulose Structure ◽  
High Dry Matter

Sugarcane is a source of roughage in animal feeding. It presents high production per unit of cultivated area, relatively easy cultivation and low cost of production per hectare, and better quality and a high dry matter (DM) yield in periods when forage is scarce. This study aimed to evaluate the effect of increasing levels of calcium hydroxide (Ca(OH)2) in sugarcane forage on chemical composition, in vitro digestibility values of DM, neutral detergent fibre (NDF) and acid detergent fibre (ADF), and kinetics of thermal decomposition processes of weight loss and heat flow. Sugarcane was collected close to the ground and 50-kg heaps of the fresh material were formed and mixed with four doses of Ca(OH)2 (0, 8, 16 and 24 g kg–1 sugarcane). Concentrations of NDF and ADF decreased linearly with increasing amount of Ca(OH)2, whereas concentration of hemicellulose increased linearly. In vitro digestibilities of DM, NDF and ADF were enhanced in a quadratic manner with increasing amounts of Ca(OH)2. The release of heat, measured by ΔH, increased linearly with increased Ca(OH)2 levels, likely due to enhanced digestibility of the fibre components. Weight loss decreased linearly between 272.2°C and 397.7°C with increased amounts of Ca(OH)2 added to sugarcane, likely due to changes in cellulose structure, which became denser and thermodynamically more stable than native cellulose following the alkaline treatment. Calcium hydroxide changed chemical composition and digestibility of the fibrous fraction of sugarcane, resulting in better nutritional value. The greatest release of heat and highest in vitro digestibility of fibre were observed when adding 15.2 g Ca(OH)2 kg–1 sugarcane; therefore, this dose is recommended to enhance the nutritive value of sugarcane as ruminant feed.

Low-cost Cu-based shape memory single crystals obtained by abnormal grain growth showing excellent superelasticity

Materialia ◽  
2019 ◽  
Vol 5 ◽  
pp. 100200 ◽  
Author(s):  
Shuiyuan Yang ◽  
Jixun Zhang ◽  
Mengyuan Chi ◽  
Yuhua Wen ◽  
Xinren Chen ◽  
...  
Keyword(s):  
Shape Memory ◽  
Single Crystals ◽  
Grain Growth ◽  
Low Cost ◽  
Abnormal Grain Growth
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