scholarly journals Reactive Ni–Al-Based Materials: Strength and Combustion Behavior

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 949
Author(s):  
Stepan Seropyan ◽  
Ivan Saikov ◽  
Dmitrii Andreev ◽  
Gulnaz Saikova ◽  
Mikhail Alymov
Keyword(s):  
Heat Treatment ◽  
Shock Wave ◽  
Flexural Strength ◽  
Combustion Rate ◽  
Rate Increase ◽  
Chemical Interaction ◽  
Experimental Results ◽  
Favorable Effect ◽  
Energy Characteristics ◽  
Combustion Behavior

The effect of PTFE, continuous boron, and tungsten fibers on the combustion behavior and strength of reactive Ni–Al compacts was examined in this study. The introduction of continuous fibers into Ni–Al compacts according to the developed scheme was found to increase the flexural strength from 12 to 120 MPa. Heat treatment (HT), leading to chemical interaction of the starting components, increases the strength of compacts at temperatures not exceeding 550 °C. The combination of reinforcement and HT significantly increases the strength without reducing reactivity. Experimental results showed that strength and combustion rate increase with the reduction in PTFE to 1 wt % in Ni–Al compacts. A favorable effect of the addition of PTFE from 5 to 10 wt % on the reduction of the threshold for the shock-wave initiation of reactions in Ni–Al was established. The obtained results can be used to produce reactive materials with high mechanical and energy characteristics.

Study on Waterproof and Water-Resistant Properties of Gypsum

2012 ◽  
Vol 476-478 ◽  
pp. 1585-1588
Author(s):  
Hong Pan ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Ordinary Portland Cement ◽  
Experimental Results ◽  
Softening Coefficient

The comprehensively modified effect of cement, VAE emulsion and self-made acrylic varnish on mechanical and water-resistant properties of gypsum sample was investigated and microstructure of gypsum sample was analyzed. Experimental results exhibit that absolutely dry flexural strength, absolutely dry compressive strength, water absorption and softening coefficient of gypsum specimen with admixture of 10% ordinary Portland cement and 6% VAE emulsion and acrylic varnish coated on its surface can respectively reach to 5.11MPa , 10.49 MPa, 8.32% and 0.63, respectively.

scholarly journals Heat treatment of a direct composite resin: influence on flexural strength

2009 ◽  
Vol 23 (3) ◽  
pp. 241-247 ◽  
Author(s):  
Caroline Lumi Miyazaki ◽  
Igor Studart Medeiros ◽  
Ivone Lima Santana ◽  
Jivaldo do Rosário Matos ◽  
Leonardo Eloy Rodrigues Filho
Keyword(s):  
Heat Treatment ◽  
Flexural Strength ◽  
Composite Resin

scholarly journals Modulation of Lithium Disilicate Translucency through Heat Treatment

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2094
Author(s):  
Seok-Ki Jung ◽  
Dae Woon Kim ◽  
Jeongyol Lee ◽  
Selvaponpriya Ramasamy ◽  
Hyun Sik Kim ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Light Scattering ◽  
Flexural Strength ◽  
Control Method ◽  
Light Transmission ◽  
Lithium Disilicate ◽  
Lower Heat ◽  
Average Size ◽  
Ball Test

The aim of this study was to present a control method for modulating the translucency of lithium disilicate ceramics through thermal refinement. Identical lithium disilicate blocks were thermally refined using four different heat treatment schedules, and the microstructure, translucency, and flexural strength of the ceramics were investigated in detail by SEM, spectroscopy, and a piston-on-three-ball test. The results showed that ceramics treated under higher heat had larger grains, with an average size between 240 and 1080 nm. In addition, a higher transmittance of all wavelengths was observed in ceramics treated under lower heat, and the transmittance in the 550 nm wavelength ranged from 27 to 34%. The results suggest that the translucency of ceramics can be modified through thermal refinement under two conditions: (1) the particle size of the ceramic is small enough to achieve minimal grain-boundary light scattering, and (2) the percentage of particles allowing visible light transmission is altered by the heat treatment.

scholarly journals The Mechanical Properties of Steel-Polypropylene Fibre Composites Concrete (HyFRCC)

2015 ◽  
Vol 773-774 ◽  
pp. 949-953 ◽  
Author(s):  
Izni Syahrizal Ibrahim ◽  
Wan Amizah Wan Jusoh ◽  
Abdul Rahman Mohd Sam ◽  
Nur Ain Mustapa ◽  
Sk Muiz Sk Abdul Razak
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Volume Fraction ◽  
Concrete Strength ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Polypropylene Fibre ◽  
Experimental Results

This paper discusses the experimental results on the mechanical properties of hybrid fibre reinforced composite concrete (HyFRCC) containing different proportions of steel fibre (SF) and polypropylene fibre (PPF). The mechanical properties include compressive strength, tensile strength, and flexural strength. SF is known to enhance the flexural and tensile strengths, and at the same time is able to resist the formation of macro cracking. Meanwhile, PPF contributes to the tensile strain capacity and compressive strength, and also delay the formation of micro cracks. Hooked-end deformed type SF fibre with 60 mm length and fibrillated virgin type PPF fibre with 19 mm length are used in this study. Meanwhile, the concrete strength is maintained for grade C30. The percentage proportion of SF-PPF fibres are varied in the range of 100-0%, 75-25%, 50-50%, 25-75% and 0-100% of which the total fibre volume fraction (Vf) is fixed at 0.5%. The experimental results reveal that the percentage proportion of SF-PPF fibres with 75-25% produced the maximum performance of flexural strength, tensile strength and flexural toughness. Meanwhile, the percentage proportion of SF-PPF fibres with 100-0% contributes to the improvement of the compressive strength compared to that of plain concrete.

Surface Oxidation Behaviour of Cubic BN Powders

2014 ◽  
Vol 602-603 ◽  
pp. 544-547
Author(s):  
Xin Yan Yue ◽  
Yue Zhang ◽  
Jian Jun Wang ◽  
Wei Wang ◽  
Hong Qiang Ru
Keyword(s):  
Heat Treatment ◽  
Surface Oxidation ◽  
Mass Gain ◽  
Oxidation Behaviour ◽  
Experimental Results ◽  
Oxidation Temperature ◽  
Oxidation Reactions ◽  
Oxidation Treatment ◽  
Treatment Processes

In order to improve the sinterability of the cBN, surface oxidation treatment was conducted to form a B2O3 film on the surface of the cBN powders. The cBN powders (d50 = 7.5 μm) were used as original powders. The heat treatment processes were 500, 800, 900, 950, 980 and 1000 °C holding for 30 minutes, respectively. The oxidation reactions which probably happened were calculated based on the thermodynamics. The experimental results showed that the oxidation starting temperature of cBN powders was higher than 800 °C. The higher the oxidation temperature, the greater the mass gain of the cBN powders.

Influence of Residual Stress on the Thermal Expansion Behavior of Electroformed Nickel Layers

2013 ◽  
Vol 662 ◽  
pp. 511-514
Author(s):  
Yi Chun Liu ◽  
Jia Min Zhang ◽  
Jian Hong Yi
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Thermal Expansion ◽  
Theoretical Analysis ◽  
Subsequent Heat Treatment ◽  
Experimental Results ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior ◽  
Electroformed Nickel ◽  
The Relationship

Nickel layers with tensile or pressure residual stress were prepared by electroforming technique from two kinds of electrolyte. Subsequent heat treatment was adopted to get the stress released. The coefficients of thermal expansion (CTEs) were measured with a thermal dilatometer and the relationship between residual stress and the measured CTEs was revealed both from experimental results and theoretical analysis.

Research in the Preparation of Paving Bricks with Construction Garbage

2013 ◽  
Vol 712-715 ◽  
pp. 917-920
Author(s):  
Lian Xi Wang ◽  
Guang Hui Pan ◽  
Fu Yong Li ◽  
Hai Ming Wang ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Experimental Results ◽  
Replacement Rate ◽  
Coarse Aggregates ◽  
Waste Concrete ◽  
Fine Aggregates ◽  
Binder Ratio ◽  
Water Binder Ratio

Construction garbage paving bricks were made of recycled coarse and fine aggregates which were prepared by the waste concrete. The influence of replacement rate of recycled coarse aggregates, water-binder ratio and excitation agent dosage on the compressive strength and flexural strength of construction garbage paving bricks were researched. The experimental results show that optimum replacement rate of recycled coarse aggregates, water-binder ratio and excitation agent dosage were 100%, 0.43 and 1.5% respectively. In this proportion, the 7d, 28d compressive strength of the products were 15.6MPa, 37.5MPa respectively, and the 7d, 28d flexural strength were 2.0MPa, 4.3MPa respectively, which fit the requirements of the Cc30 level of compressive strength and the Cf4.0 level of flexural strength involved in JCT 446-2000 "concrete pavers".

Experiment on the Attenuation Characteristics of Shock Wave Interacting with Open and Closed Foam

2014 ◽  
Vol 1035 ◽  
pp. 445-452
Author(s):  
Jian Wang ◽  
Bao Gui Wang ◽  
Gang Tao
Keyword(s):  
Shock Wave ◽  
Internal Friction ◽  
Dynamic Behavior ◽  
Solid Phase ◽  
Experimental Results ◽  
Reflection And Transmission ◽  
Attenuation Characteristics

For understanding the dynamic behavior of open and closed foam subject to a shock wave, this paper through experiments, to gain a deeper understanding of the incidence, reflection and transmission of a shock wave when it interacted with cellular foam. Moreover, by analyzing the loss of the peak overpressure and positive impulse, we were able to respectively know the positive impulse of the incidence, reflection and transmission shock wave. The experimental results indicated that the attenuation capability for foam to the shock wave was caused by the internal friction and deformation of solid phase, which would absorb the energy of the shock wave. From the results we gain an understanding that the mechanical phenomenon of open foam to shock wave are not fully consistent with those of closed foam , while the attenuation of open foam to shock wave is more effective than that of closed foam.

Predictive Kinetics-based Model for Shock-activated Reaction Synthesis of Ti3SiC2

2005 ◽  
Vol 20 (6) ◽  
pp. 1476-1484
Author(s):  
Jennifer L. Jordan ◽  
John A. Pelesko ◽  
Naresh N. Thadhani
Keyword(s):  
Heat Treatment ◽  
Activation Energy ◽  
Steady State ◽  
Predictive Model ◽  
Heat Dissipation ◽  
Experimental Results ◽  
Reaction Synthesis ◽  
Synthesis Conditions ◽  
Type Reaction ◽  
Activated State

A kinetics model based on mass and heat transport has been developed for Ti3SiC2 formation via shock-activated reaction synthesis of powder precursors. The model allows prediction of heat treatment conditions under which an otherwise steady-state reaction is taken over by a “run-away” combustion-type reaction during post-shock reaction synthesis of Ti3SiC2. Shock compression of Ti, SiC, and graphite precursors generates a densely packed highly activated state of reactants, which lowers the activation energy and results in an increased rate of formation of Ti3SiC2 at a lower temperature and in shorter times. The predictive model correlated with experimental results of fraction reacted as a function of time at heat-treatment temperatures of 1400 and 1600 °C illustrates an increased rate of reaction due to lowering activation energy, which also results in the reaction at 1600 °C being taken over by a “run-away” combustion-type reaction, as the rate of heat release due to reaction exceeds the rate of heat dissipation through the compact. Correlation of the model with experimental results illustrates that the predictive model can be used to optimize reaction synthesis conditions in shock-densified compacts of Ti3SiC2-forming powder precursors, to better understand the processes leading to a steady-state reaction being taken over by the combustion mode.

A Brief Review on Validation for Heat Treatment Simulation

2021 ◽  
Author(s):  
Kyozo Arimoto
Keyword(s):  
Heat Treatment ◽  
Measurement Data ◽  
Strain Analysis ◽  
Experimental Results ◽  
Stress Distributions ◽  
Simulation Functions ◽  
Basic Functions ◽  
Hardness Prediction ◽  
Quenched Steel ◽  
Complex Phenomena

Abstract Heat treatment simulation has progressed to the stage where several commercial software are available. Validations of simulation functions using experimental results contributed to this realization. Organizing information on the validations may be effective for maintaining the functions and educating users about the nature of the phenomena. For this reason, the author here briefly reviews mainly his validation cases. Since experiments using specimens having relatively simple shapes can reveal the essence of complex phenomena, the results have been used in the validations. When the basic functions such as heat transfer, phase transformation, latent heat, and hardness prediction were comprehensively validated in the early stages of software development, the author used experimental results of the inverse hardening in quenched steel cylinders. After that, his validations of the software at the stage where adding stress and strain analysis functions, used effectively measurement data of length and diameter changes, and residual stress distributions in normally quenched steel cylinders. While, it was also worth to validate curving in long specimens cooled unevenly, which included a case of specimens with a similar cross-section to the Japanese sword. In addition, the author validated distortions and residual stresses in carburized and quenched, induction hardened, and also nitrided specimens.

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