Microstructure of Silicon Nitride Fibers at Elevated Temperatures

2017 ◽  
Vol 898 ◽  
pp. 1705-1711 ◽  
Author(s):  
Jun Zhe Li ◽  
Xun Sun ◽  
Hai Tao Liu ◽  
Hai Feng Cheng ◽  
Xiao Shan Zhang
Keyword(s):  
Heat Treatment ◽  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Treatment Process ◽  
Elevated Temperatures ◽  
Heat Treatment Process ◽  
Amorphous Silicon Nitride ◽  
Heat Treated ◽  
Strength Retention ◽  
Heat Treated Temperature

The composition and microstructure of silicon nitride fibers after heat-treatment at elevated temperatures were investigated by XRD, NMR, XPS, SEM and TEM analyses. The results show that as-received fibers consisted of amorphous silicon nitride, and a little Si-C-O structure. During heat-treatment process, α-Si3N4 and β-Si3N4 formed resulting from the crystallization of amorphous silicon nitride, and the formation of β-SiC derived from the decomposition of Si-C-O structure. As heat-treated temperature increased from 1400oC to 1600oC, the above phenomenon become obvious, indicating that the fiber would possess high serving life with serving temperature lower than 1400oC. The tensile strength of fibers stays stable when heat-treated temperature was below 1200oC, while the strength retention of fibers sharply decreased to 50% after heat-treatment at 1400°C.

Characteristics and Applications of Nanostructured Nitrides Synthesized by Vapor Phase Reactions

2005 ◽  
Vol 876 ◽  
Author(s):  
Gerald Ziegenbalg ◽  
Carsten Pätzold ◽  
Ute Ŝingliar ◽  
Rico Berthold
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Vapor Phase ◽  
Elevated Temperatures ◽  
Catalyst Support ◽  
Chemical Properties ◽  
Molar Ratio ◽  
Basic Catalyst ◽  
Metal Chlorides ◽  
Amorphous Silicon Nitride

AbstractGas phase ammonolysis of volatile metal chlorides at elevated temperatures is a favorable way to produce nitride or oxynitride nanopowders. Their composition as well as the physico-chemical properties is determined by reaction temperature, molar ratio of the reactants and the residence time of the gases in the reaction zone. Both single and multi component powders can be obtained. Typical particle sizes are in the range of 50 to 350 nm. The specific surface can reach values up to 300 m2/g. Microporous analysis revealed the presence of pores with a diameter between 0.6 and 0.7 nm in amorphous silicon nitride. The powders can be used, depending on the characteristics, as catalyst or basic catalyst support. The paper gives an overview about vapor phase synthesis of single and multi component nitrides as well as the use of amorphous silicon nitride as a basic catalyst support for dehydrogenation of propane.

High Tensile Strength of Drawn Gold

2005 ◽  
Vol 495-497 ◽  
pp. 907-912 ◽  
Author(s):  
Suk Hoon Kang ◽  
Hee Suk Jung ◽  
Woong Ho Bang ◽  
Jae Hyung Cho ◽  
Kyu Hwan Oh ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Tensile Strength ◽  
Treatment Process ◽  
Gold Wire ◽  
Equivalent Strain ◽  
Heat Treatment Process ◽  
High Tensile Strength ◽  
Heat Treated ◽  
Gold Wires

This paper studies the microstructure of drawn gold wires to equivalent strain of 10 and to equivalent strain of 8.5 then heat-treated. The texture of gold wire drawn to strain of 10 is mainly composed of <100> and <111> fibers. Tensile strength of the gold wire increases with <111> fiber fraction, while the grain size does not appear to affect the tensile property. With an exception at heat treatment at 600oC, the texture of gold wire drawn the strain of 8.5 is replaced with <100> fiber component by heat treatment process at 400~700oC. Heat treatment at 600oC produces <110> fiber or <112> fiber, depending upon annealing time.

Failure Analysis and Study on Heat Treatment Process of Grate Bars Used in Sintering Trolley

2014 ◽  
Vol 1061-1062 ◽  
pp. 454-459
Author(s):  
An Min Li ◽  
Ding Ma ◽  
Qi Feng Zheng ◽  
Ruo Huai Chen ◽  
Qiang Li ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Residual Austenite ◽  
Shrinkage Porosity ◽  
Heat Treatment Process ◽  
Fracture Characteristics ◽  
Heat Treated ◽  
Primary Means ◽  
Optimum Heat ◽  
Optimum Heat Treatment

The as-cast grate bar structure used in sintering trolley is primarily comprised of austenite and eutectic (eutectic austenite and eutectic carbide).The austenite is dendrite, while the carbides are reticular and chrysanthemum-like. The failed grate bar structure primarily consists of ferrite, carbide, martensite and residual austenite; cavity shrinkage and shrinkage porosity exist in the structure, and the fracture exhibits typical cleavage fracture characteristics. The primary means of failure are abrasion and fracture. The secondary carbides precipitated in the sample (quenching (1050°C+2.5h)+ tempering (390°C+2.5h)) and the other one (quenching (1050°C+2.5h)+ tempering (420°C+2.5h) ) are dispersed and refined. Compared with the as-cast one, their relative abrasion resistance performances respectively are 0.8645 and 0.8752.The values of hardness and impact toughness of the samples heat-treated are greater than those of the as-cast grate bar. The optimum heat treatment process is as follows: quenching (1050°C,2.5h) + tempering (390°C~420°C,2.5h)

scholarly journals Optimisation of Heat Treatment Process for Damping Properties of Mg-13Gd-4Y-2Zn-0.5Zr Magnesium Alloy Using Box–Behnken Design Method

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 157 ◽  
Author(s):  
Jun Zhang ◽  
Ziming Kou ◽  
Yaqin Yang ◽  
Baocheng Li ◽  
Xiaowen Li ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Treatment Process ◽  
High Strength ◽  
Damping Capacity ◽  
Heat Treatment Process ◽  
Damping Properties ◽  
Heat Treated ◽  
Second Phases ◽  
Imagej Software

High damping magnesium alloys have poor mechanical properties, so it is necessary to investigate the damping properties of high-strength wrought magnesium alloys to effectively reduce vibration and noise in mechanical engineering. The aim of this work is to improve the mechanical damping performance of a novel high-strength Mg-13Gd-4Y-2Zn-0.5Zr magnesium alloy by optimising the heat treatment process. The mechanical damping coefficient, considering not only damping capacity but also the yield strength, is selected as one of the evaluation indexes. The other evaluation index is the tensile strength. The solid solution and ageing treatment were optimised by Box-Behnken method, an efficient experimental design technique. Heat treatment experiments based on the optimal parameters verified that the best process is a solution at 520 °C for 10 h followed by ageing at 239 °C for 22 h. The damping coefficient reaches 0.296, which is 73.1% higher than that before heat treatment. There was a good agreement between the experimental and Box-Behnken predicted results. The microstructure, morphology and composition of the second phases after heat treatment were analysed by SEM, XRD and EDS. Due to the high content of alloying elements in Mg-13Gd-4Y-2Zn-0.5Zr alloy, there are a large number of second phases after heat treated. They mainly include layer, short rod-shaped, bulk long period stacking order (LPSO) Mg12YZn and granular Mg5Gd phases. It was found that the area fraction of the second phases has an extreme effect on the damping capacity and short rod-shaped LPSO can effectively improve the damping capacity of heat-treated Mg-13Gd-4Y-2Zn-0.5Zr alloy. The volume fraction of the second phases was analysed by ImageJ software. It was concluded that the smaller the area occupied by the second phases, the better the mobility of the dislocation, and the better the damping performance of the alloy. The statistical analysis results obtained using ImageJ software are consistent with the experimental results damping capacity.

scholarly journals Effect of Heat Treatment on Microstructure and Mechanical Properties of a Selective Laser Melting Processed Ni-Based Superalloy GTD222

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3668
Author(s):  
Tian Xia ◽  
Rui Wang ◽  
Zhongnan Bi ◽  
Guoliang Zhu ◽  
Qingbiao Tan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Treatment Process ◽  
Heat Treatment Process ◽  
Laser Melting ◽  
Microstructure Characteristics ◽  
Microstructure And Mechanical Properties ◽  
Heat Treated

Additive manufacturing (AM) of nickel-based superalloys is of high interest for application in complex hot end parts. However, it has been widely suggested that the microstructure-properties of the additive manufacturing processed superalloys are not yet fully clear. In this study, the GTD222, an important superalloy for high-temperature hot-end part, were prepared using selective laser melting and then subjected to heat treatment. The microstructure evolution of the GTD222 was investigated and the mechanical properties of heat treated GTD222 were tested. The results have shown that the grain size of the heat treated GTD222 was close to its as-built counterparts. Meanwhile, a large amount of γ’ and nano-scaled carbides were precipitated in the heat treated GTD222. The microstructure characteristics implied that the higher strength of the heat treated GTD222 can be attributed to the γ’ and nano-scaled carbides. This study provides essential microstructure and mechanical properties information for optimizing the heat treatment process of the AM processed GTD222.

scholarly journals Study on the Ignition Performance of TaN Transducer by Heat Treatment

CONVERTER ◽  
2021 ◽  
pp. 347-353
Author(s):  
Xiaoming Ren, Et al.
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Heat Treatment Process ◽  
Ignition Voltage ◽  
Cooling Method ◽  
Heat Treated ◽  
Before And After ◽  
Film Transducer

In order to obtain good TaN film transducer and reduce its ignition voltage, the influence of the setting position and cooling method of the heat treatment process on the TaN film transducer were compared and analyzed. By measuring the square resistivity, SEM and XRD, the performance of the film before and after heat treatment were characterized. The ignition voltage of the TaN film transducer was tested, and the results showed that the ignition voltage of the heat-treated TaN film transducer could be reduced a lot. It provided a technical way for the micro-energy of MEMS pyrotechnics.

scholarly journals Influence of Heat Treatment Process on the Acceptability of Pasteurized Beetroot

2014 ◽  
Vol 9 (1-2) ◽  
Author(s):  
Dragan P Vujadinović ◽  
Božana V Odžaković ◽  
Radoslav D Grujić ◽  
Milija Perić
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Color Change ◽  
Heat Treatment Process ◽  
Optimal Conditions ◽  
Optimum Time ◽  
Treatment Conditions ◽  
Heat Treated ◽  
Treatment Procedures ◽  
Temperature Time

Abstract: A heat-treated beet is defined as a food that is subject to a temperature, high enough to destroy microorganisms and to preserve all the nutrients. The aim of the study presented in this paper was to investigate the effect by cooking on the properties of heat threated beetroot in the temperature range between 75 °C and 115 °C during the 40, 50 and 60 minutes of cooking. In order to determine the optimal conditions for the implementation of various heat treatment procedures consequently, was followed the influence of heat treatment conditions (temperature/time) on the composition, rheological properties, pH, color change (L*, a*, b*) and sensory characteristics during the development of the “pasteurized/sterilized” beet product. This study has shown that the optimum time and temperature for processing of beetroot is 105 °C at 50 minutes. Samples of beetroot, processed under these conditions had the best softness, the most acceptable taste and color (sensory and instrumentally determined).

scholarly journals Preparation of SnO2 nanotubes via a template-free electrospinning process

RSC Advances ◽  
2020 ◽  
Vol 10 (37) ◽  
pp. 22113-22119 ◽  
Author(s):  
Takahiro Suzuki ◽  
Jing Cheng ◽  
Li Qiao ◽  
Yan Xing ◽  
Meng Fei Zhang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Structural Evolution ◽  
Electrospinning Process ◽  
Heat Treatment Process ◽  
Heat Treated Sample ◽  
Heat Treated ◽  
Treated Sample ◽  
Template Free ◽  
Spun Fibers

The morphology of the prepared samples. (a) FESEM images of each temperature which shows the structural evolution of as-spun fibers to nanotube during the heat treatment process. (b) TEM images of 600 °C heat-treated sample.

Processing and characterization of high strength dual-phase steel by two-step intercritical heat treatment process

2018 ◽  
Vol 233 (3) ◽  
pp. 581-588 ◽  
Author(s):  
Praveen Singh ◽  
Satnam Singh ◽  
Sanchit Mewar
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Treatment Process ◽  
Heat Treatment Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Treated Steel ◽  
Heat Treated ◽  
Intercritical Heat Treatment ◽  
Heat Treated Steel

A simple approach of two-step intercritical heat treatment has been employed to study the effect of heat treatment on the evolution of microstructures and their effect on the mechanical properties of alloy steel (AISI 1012). The selected steel samples were directly placed in the preheated furnace and were progressively heat treated in two steps, intercritically between the Ac1–Ac3 temperature range. Immediate water quenching (preheated at 30 ℃) was carried out after heat treatment cycles. The processed steels were characterized by examining the X-ray diffraction patterns, microstructures, Vickers microhardness, and tensile strength. The normalized X-ray diffraction results of heat-treated steels revealed the substantial growth in the martenistic phases. The microstructures of heat-treated steel revealed the formation of needle-shape-like structures, which corresponds to the martenistic phase. The increased formation of martenistic phase due to the intercritical heat treatment process improved the overall microhardness (from 188 ± 9 HV of the parent steel to 412 ± 32 HV for 800 ℃ heat-treated steel) up to 2.2 times. The presence of soft and ductile (ferritic and pearlite) phases simultaneously with tough and strong (martenistic) phase allowed the improvement in the ultimate tensile strength. In comparison to parent steel with tensile strength of 510 ± 15 MPa, the intercritical heat treatment steel at 800 ℃ revealed 169.6% higher tensile strength of 1375 ± 35 MPa. However, percentage elongation was reduced by 60%, i.e. from 13 ± 1% for parent steel to 5.2 ± 2% of intercritical heat treatment steel (processed at 800 ℃). An overall study revealed that by a proper intercritical heat treatment process, dual-phase steels with better structure–properties correlation can be obtained for industrial applications.

scholarly journals Advanced Distortion Control for Heat Treated Components

2019 ◽  
Author(s):  
Tom Hart ◽  
Maciej Korecki
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Case Depth ◽  
Hardness Profile ◽  
Heat Treatment Process ◽  
Heat Treated ◽  
Minimal Distortion ◽  
Distortion Control ◽  
Identical Manner ◽  
Unique Method

Abstract Material distortion is an undesired characteristic observed when a produced component requires a thermo-chemical heat treatment process followed by a rapid quench to obtain desired mechanical and metallurgical properties with uniform case depth and hardness profile. Due to the distortion taking place during this process, the manufacturer is faced with the costly choice of leaving excess material on a machined component before the heat treatment process, only to be removed after the heat treatment process by post heat treatment manufacturing methods. When steps are taken to reduce material distortion (prior to hard machining operations), manufacturers can significantly reduce costs and subsequently speed up the overall manufacturing process. This paper will discuss the unique method of distortion control for heat treated and quenched components by use of a 4-Dimensional High-Pressure Gas Quench (4D Quench®) technique. This system has the ability to quench a single component without fixturing versus either a free quench or complex press quench approach. The 4D Quench® process results in components being individually quenched in an identical manner while having minimal distortion in relation to the green component. 4D Quench® systems are easily integrated into machining centers improving lead time and costs associated with traditional heat treatment processes.

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