Role of Sintering Parameters on Microstructure Development and Mechanical Properties of Sinter/hip Silicon Nitride

1992 ◽  
Vol 287 ◽  
Author(s):  
Arnd Kühne ◽  
Rainer Oberacker ◽  
Georg Grathwohl
Keyword(s):  
Mechanical Properties ◽  
Silicon Nitride ◽  
Process Parameters ◽  
Systematic Variation ◽  
Microstructure Development ◽  
Creep Tests ◽  
Nitride Material

ABSTRACTSinter/HIP consolidation with systematic variation of all relevant process parameters was performed for low additive (Y2O3-A12O3) silicon nitride material. With SEM-investigations as well as bending and creep tests the relevance of process parameters on microstructure development and mechanical properties was studied.

scholarly journals Silicon Nitride-Based Composites with the Addition of CNTs—A Review of Recent Progress, Challenges, and Future Prospects

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2799
Author(s):  
Awais Qadir ◽  
Péter Pinke ◽  
Ján Dusza
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Carbon Nanotube ◽  
Silicon Nitride ◽  
Wear Rate ◽  
Recent Progress ◽  
Bending Strength ◽  
Microstructure Development ◽  
Future Prospects ◽  
Microstructure Characteristics

In this overview, the results published to date concerning the development, processing, microstructure characteristics, and properties of silicon nitride/carbon nanotube (Si3N4 + CNTs) composites are summarized. The influence of the different processing routes on the microstructure development of the Si3N4 + CNTs is discussed. The effects of the CNTs addition on the mechanical properties—hardness, bending strength and fracture toughness—and tribological characteristics—wear rate and coefficient of friction—are summarized. The characteristic defects, fracture origins, toughening and damage mechanisms occurring during the testing are described. The influence of the CNTs’ addition on the thermal and functional properties of the composites is discussed as well. New trends in the development of these composites with significant potential for future applications are outlined.

scholarly journals Comparison of Numerical Simulation and Experiment for the Microstructure Development of a Cold-Rolled Multiphase Steel during Annealing

2016 ◽  
Vol 854 ◽  
pp. 167-173 ◽  
Author(s):  
Norbert Kwiaton ◽  
Roman Kuziak ◽  
Maciej Pietrzyk
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Process Parameters ◽  
Temperature Cycle ◽  
Microstructure Development ◽  
Tempered Martensite ◽  
Temperature Cycles ◽  
Simulation And Experiment ◽  
Cold Rolled ◽  
Multiphase Steel

JAMK model, developed as part of RFSR-project “VADPsheets”, was applied to analyse different time temperature cycles from industrial time temperature cycle. The results of numerical simulation are compared with experimentally determined mechanical properties and microstructures. By distinguishing of recrystallized ferrite, ferrite after transformation, tempered martensite, bainite and martensite can be explained the experimentally obtained mechanical properties. The results of simulation can be used to optimizing the properties and to generate a better understanding of process parameters.

Thermal and Loading Effects on Mechanical Properties of a Hot Isostatically Pressed Si3N4

1994 ◽  
Author(s):  
Jagannathan Sankar ◽  
Jayant Neogi ◽  
Suneeta S. Neogi ◽  
Marvln T. Dixie ◽  
Ranji Vaidyanathan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Silicon Nitride ◽  
Elevated Temperatures ◽  
Heat Engine ◽  
Tensile Tests ◽  
Tensile Creep ◽  
Uniaxial Tensile ◽  
Creep Tests ◽  
Loading Effects

The effect of thermal soaking on the mechanical properties of a candidate material for advanced heat engine applications namely, hot isostatically pressed (HIPed) silicon nitride (GTEPY6) are reported here. Pure uniaxial tensile tests conducted at room and at elevated temperatures indicated that the tensile strength of this material dropped significantly after 1000°C. The residual tensile strength of PY6 material after thermal soaking at 1200° and 1300°C was also investigated. Test results showed that thermal soaking at 1200° and 1300°C increased the residual tensile strength. The thermal soaking time had a greater effect on the residual tensile strength at 1300°C. Tensile creep tests performed at 1200° and 1300°C showed that the steady state creep rate was influenced by both the temperature and the applied stress. The higher stress exponent in HIPed as compared to a sintered silicon nitride shows higher creep resistance in the case of HIPed materials.

Investigation of Mechanical Properties and Microstructure Development of AZ61 Alloy during Rolling, Forging and ECAP

2013 ◽  
Vol 742 ◽  
pp. 175-181
Author(s):  
Lenka Kunčická ◽  
Radim Kocich
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Fine Particles ◽  
Size Reduction ◽  
Microstructure Development ◽  
Alloy Structure ◽  
A Value ◽  
Az61 Alloy ◽  
Plastic Forming

Results of experiments, focused on development of modified AZ61 alloy structure after hot forming, are summarized in this paper. Microstructure changes of the alloy after rolling and forging at temperatures of 380°C and after ECAP processed at 250°C were observed. After forging, the original grain size was reduced almost 14 times down to a value around 9 μm. After ECAP the grain size reduction was even better, almost 60 times. Important role of the ß-phase (Mg17Al12) in this alloy, during plastic forming, was confirmed. Independently of processing technology, the best final properties of the AZ61 alloy were supported with very fine particles distributed in the Mg matrix. The experiment succeeded in proving the influence of precipitates on restoration processes too.

The Influence of Phase Transformations on Creep Resistance in Fe-Ni-Cr Alloys for Reformer Tube Applications

2007 ◽  
Author(s):  
Johanne Laigo ◽  
Franck Tancret ◽  
Rene´ Le Gall ◽  
Fre´de´ric Christien ◽  
Jader Furtado
Keyword(s):  
Mechanical Properties ◽  
Phase Transformations ◽  
Creep Resistance ◽  
Critical Role ◽  
Thermal Conditions ◽  
Dislocation Motion ◽  
Creep Tests ◽  
Modelling Techniques ◽  
Heat Resistant Steels

Heat resistant steels of the HP-series have widespread uses in the petrochemical industry in pyrolysis and reformer furnaces. The alloys are carbon-rich Fe-Ni-Cr alloys, with additions like Mn, Si, Nb, Ti, W... The typical microstructure of as-cast HP alloys is an austenite matrix with intergranular eutectic-like primary chromium carbides of the M7C3 type and niobium carbides of the MC type. Upon ageing, phase transformations occur. Intragranular secondary M23C6 carbides precipitate, which is thought to restrict dislocation motion, and intergranular M7C3 transforms into M23C6. Under certain thermal conditions, a partial transformation of the primary niobium carbides into a nickel-niobium silicide called G phase can occur. These phases may play a critical role during creep, but neither their role on mechanical properties nor the mechanisms of phase transformations are clearly identified. The aim of this study is to understand the role of each phase or phase transformation in the creep resistance of HP alloys. Consequently, a critical review of phase formation and transformations in such alloys is presented using a set of experimental and modelling techniques (electron microscopy, Castaing microprobe, creep tests at high temperature and neural networks modelling of mechanical properties...).

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

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