scholarly journals Grain-Size Effects on Multi-Wire Slurry Sawing of Translucent Alumina Ceramics

Ceramics ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 428-439
Author(s):  
Lea Schmidtner ◽  
Mathias Herrmann ◽  
Christos G. Aneziris
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Size Effects ◽  
Material Removal ◽  
Alumina Ceramic ◽  
Alumina Ceramics ◽  
Ceramic Substrates ◽  
Treatment Processes ◽  
Sawing Process ◽  
Cut Surface

The technology of multi-wire sawing is well established in the production of silicon wafers but can also be applied in the production of ceramic substrates. In this study, the influence of the Al2O3-grain size of the alumina ceramic on the efficiency of the multi-wire slurry process was investigated. The grain size of HIPed alumina ceramics was changed by heat treatment processes at 1350 °C and 1400 °C. A B4C slurry was used for the investigation of the cutting of high purity alumina ceramic. With increasing grain size of the ceramic, the efficiency of the sawing process increases. The analysis of the as-cut surface morphology of the substrates shows a change in material removal from trans- to intergranular micro-fracture with increasing grain size. Furthermore, grain coarsening leads to substrates with increased roughness values and reduced biaxial strength.

The Method of Eliminating Banded Structure and the Effects of Banded Structure on the Transverse Properties in 20G Steel

2013 ◽  
Vol 347-350 ◽  
pp. 1171-1175 ◽  
Author(s):  
Bin Wang ◽  
Hong Mei Hu ◽  
Cui Zhou
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Stress Concentration ◽  
Base Metal ◽  
Metallic Inclusion ◽  
Banded Structure ◽  
Grain Sizes ◽  
Fine Grain ◽  
Treatment Processes ◽  
Metallic Inclusions

The transverse properties were inferior to the longitudinal properties for the existence of banded structure in 20G steel. In order to eliminate the banded structure and improve the transverse performance of 20G steel, different heat treatment processes were adopted. The results showed that conventional normalizing could reduce the banded structure and refine the grain sizes. When 20G was heated with 10°C/min heating rated and then held at 920°C for 2h, the banded structure in the steel was almost eliminated and the microstructure was homogeneous with fine grain size, the strength increased by 14%. The non-metallic inclusion and carbide in the microstructure leaded to stress concentration and separation with the base metal. To some extent, heat treatment can improve the distribution and form of non-metallic inclusions.

Researches on Microstructures and Mechanical Properties of Extruded Mg-Zn-Zr-Y Alloy

2007 ◽  
Vol 353-358 ◽  
pp. 715-717
Author(s):  
Jian Peng ◽  
Rong Shen Liu ◽  
Ding Fei Zhang ◽  
Cheng Meng Song
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Aging Treatment ◽  
High Strength ◽  
Treatment Processes ◽  
Medium Strength ◽  
Microstructures And Mechanical Properties ◽  
Extruded Products

The microstructures and mechanical properties of Mg-Zn-Zr-Y alloy extruded bar with different heat treatment processes were investigated, including solution treatments of 400 oC, 450 oC and 500 oC for 3 hours followed by 170 oC×24h aging treatment, and solely aging treatments of 160 oC, 180 oC for 24hours without solution after extruding. By comparing the grain size, strength and elongation of the samples, the heat treatment processes for extruded products with high strength and with medium strength were recommended.

Effect of Phase Composition and Microstructure of Oxide Scale on the Corrosion Resistance of SS400 Hot Rolled Strip

2011 ◽  
Vol 399-401 ◽  
pp. 1951-1957
Author(s):  
Xian Liang Zhou ◽  
Min Zhu ◽  
Xiao Zhen Hua ◽  
Zhi Guo Ye ◽  
Xia Cui ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Corrosion Resistance ◽  
Oxide Scale ◽  
Electrochemical Impedance ◽  
Rolled Strip ◽  
Fine Grain ◽  
Treatment Processes ◽  
The Difference ◽  
Hot Rolled

Different phase compositions and microstructures of oxide scales were formed on the surface of SS400 hot rolled alloys by employing various heat treatment processes. Cyclic wet-dry immersion corrosion test, electrochemical impedance spectroscopy were used to investigate the corrosion resistance of strips with scales fabricated by different heat treatment processes. The results reveal that difference in the corrosion resistance of the various scales is due to the difference in the grain size of Fe3O4phase. Furthermore, the difference in the corrosion resistance of different oxide phases, exhibited by various scales, also render the strips to give various corrosion behaviors. It is surmised that the strip with oxide scale, which consist of a small mount of the outer layer Fe2O3phase distributed continuously and a large quantity of the inner layer Fe3O4phase with the fine grain size, and possess nice compactness, continuity, integrity in the morphology structure, has the best corrosion resistance.

scholarly journals The effect of Nb content on precipitates, microstructure and texture of grain oriented silicon steel

2019 ◽  
Vol 38 (2019) ◽  
pp. 628-638 ◽  
Author(s):  
Yong Wang ◽  
Chengyi Zhu ◽  
Guangqiang Li ◽  
Yu Liu ◽  
Bowen Zhou
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Hot Rolling ◽  
Silicon Steel ◽  
Pinning Force ◽  
Number Density ◽  
Goss Texture ◽  
Treatment Processes ◽  
Nb Content ◽  
Evolution Of Precipitates

AbstractNiobium has the potential as an inhibitor forming element in grain oriented silicon steel. The grain oriented silicon steels with different Nb contents (0.028 wt% and 0.052 wt%) were prepared, and the effect of Nb content on the evolution of precipitates, microstructure and texture were investigated by the various analysis methods and thermodynamic calculations. The results show that the smaller size and larger number density of precipitates were obtained in the sample with low Nb steel after hot rolling. In the process of normalization, Nb(C, N) are more inclined to precipitate along the dislocations caused by hot rolling, contributing to finer and more dispersed precipitates in normalized bands. The finer and more dispersed precipitates in 0.028% Nb containing silicon steel perform a stronger pinning force during whole heat treatment processes, resulting in the smaller grain size and higher intensity of Goss texture in the specimen containing 0.028%Nb. After normalization, the intensities of Goss texture in both steels decrease.

Modelling and optimization of technological parameters in hot abrasive jet machining of alumina ceramic

2019 ◽  
Vol 107 (6) ◽  
pp. 603 ◽  
Author(s):  
Ranjit Kumar Behera ◽  
Sudhansu Ranjan Das
Keyword(s):  
Grain Size ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Predictive Modelling ◽  
Alumina Ceramic ◽  
Technological Parameters ◽  
Flat Surfaces ◽  
Response Characteristics ◽  
Abrasive Jet Machining

The present work focuses on the experimental investigation of hot abrasive jet machining (HAJM) and precision drilling operation on flat surfaces of K-60 alumina ceramic material using different grades of silicon carbide abrasives. The machining AJM setup is designed based on fluidized bed mixing chamber along with pressurized powder feed chamber. The experiments are performed as per Box-Behnken design of experiments (BBDOEs) with four process parameters (pressure, stand of distance, abrasive temperature and grain size) for parametric optimization in order to control the two technological response characteristics (material removal rate, flaring diameter) of the precision holes on K-60 alumina. Analysis of variance (ANOVA), response surface methodology (RSM) and genetic algorithm (GA) are subsequently proposed for predictive modelling and process optimization. Result shows that application of hot abrasives in AJM process has excellent performance in terms of improved material removal rate, and minimum dimensional deviation of drilled hole. Multi-response optimization GA technique presented the optimal setting of machining variables in HAJM process at air pressure of 6.682 kgf/cm2, abrasive temperature of 60.6 °C, stand-off-distance of 7.1124 mm, abrasive grain size of 275.755 µm, with estimated maximal material removal rate of 0.005 gm/s and minimal flaring diameter of 6.382 mm. The methodology described here is expected to be highly beneficial to manufacturing industries.

Bonds of Electroplated Diamond Tools for Optical Glass Machining

2006 ◽  
Vol 304-305 ◽  
pp. 81-84
Author(s):  
Ai Bing Yu ◽  
A.J. Wang ◽  
C.G. Luan ◽  
S.F. Chen
Keyword(s):  
Heat Treatment ◽  
Material Removal Rate ◽  
Material Removal ◽  
Diamond Tool ◽  
Optical Glass ◽  
Removal Rate ◽  
Diamond Tools ◽  
Treatment Processes ◽  
Nickel Cobalt ◽  
Grinding Ratio

Bonds of electroplated diamond tools are investigated through the studies of microstructures and properties. Three coatings for tool bonds, nickel, nickel-cobalt and bright nickel, were fabricated with electrodeposition processes, and were heat-treated with different temperatures. The hardness and microstructures of coatings were measured and observed. Optical glass K9 was machined with fabricated electroplated diamond tools to compare material removal rate and grinding ratio. The grain sizes of three bond coatings are different. The laminar structures of nickel-cobalt and bright nickel coatings turn to fine columnar structure after heat treatment processes. With heat treatment of 200°C temperature, bright nickel electroplated diamond tool presents highest values of material removal rate and grinding ratio. The research results show that better microstructures and property of bond for electroplated diamond tool can be obtained by selecting proper electroplating technology and heat treatment processes.

scholarly journals Multi-Wire Sawing of Translucent Alumina Ceramics

2020 ◽  
Vol 4 (1) ◽  
pp. 2
Author(s):  
Lea Schmidtner ◽  
Hannes Heinrich ◽  
Marcel Fuchs ◽  
Anke Pötzsch ◽  
Stefan Janz ◽  
...  
Keyword(s):  
Process Development ◽  
Alumina Ceramics ◽  
Ceramic Substrates ◽  
Fine Grained ◽  
Sensor Applications ◽  
Technical Ceramics ◽  
The Wire ◽  
Sawing Process ◽  
First Time

Multi-wire sawing has emerged as the leading technology in wafer production for a variety of semiconductor materials. This study investigates the process stability and efficiency of conventional semiconductor multi-wire slurry saws in routinely machining translucent, high-density alumina ceramics. The brittle and fine-grained translucent alumina ceramics with extreme hardness and wear resistance represents a major challenge for the process. The alumina ceramic substrates are used for sensor applications, energy storage technology and applications in power electronics. An ideal adaptation of the sawing process parameters to the workpiece properties guarantees the efficiency of the slurry sawing process and the quality of the ceramic wafers. An indicator of the efficiency and cutting ability of the sawing process is the size of the bow of the wire web. The first time was shown that the wire bow can be used for the characterization of the sawing processes for hard and brittle technical ceramics. It was found that a longer workpiece length, a higher number of wafers and stronger abrasive wear lead to an increased size of the bow. The rocking frequency has no measurable influence on the size of the bow. Knowledge of these relations is an extremely valuable tool in the sawing process development for hard and brittle technical ceramics.

scholarly journals Influence research of temperature heat treatment on the microstructure of alumina ceramics

2020 ◽  
Vol 120 ◽  
pp. 134-143
Author(s):  
V. V. Martynenko ◽  
Р. O. Kushchenko ◽  
K. I. Kushchenko ◽  
Yu. O. Krakhmal ◽  
E. L. Karjakina ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Moisture Content ◽  
Slip Casting ◽  
Microscopic Analysis ◽  
Alumina Ceramic ◽  
Al2o3 Content ◽  
Alumina Ceramics ◽  
Electron Microscopic ◽  
Ceramic Samples ◽  
Α Al2o3

The JSC "URIR named after A. S. Berezhnoy" developed and introduced the technology of highly refractory alumina extra-dense ceramics. It is known that, the structure and properties of alumina ceramics in many cases depend on the temperature of its heat treatment, the holding time at the final temperature, the thermal unit, and a number of other factors. In order to study the processes of structure formation during of heat treatment the microstructure of alumina ceramic samples of two compositions (composition 1 with a moisture content of 30 %, as well as with dispersing and hardening additives, and composition 2 with a moisture content of 20 % only with dispersing additive) which were made by slip casting aqueous alumina slips based on reactive alumina α–from with Al2O3 content over 99 %, specific surface ~ 9 m2/g by electron microscopic analysis was studied. It was established that, after heat treatment at 1000 °C the beginning of sintering and recrystallization of corundum grains are observed, after heat treatment at 1200 °C take place packing of structure and recrystallization of α–Al2O3. After firing at 1400 °C the microstructure of samples composition 1 is represented to a large extent by crystals of tabular corundum with a particle size ~ 0.5—5.5 μm, predominant — ~ 2.5—3.0 μm. After firing at 1400 °C the microstructure of samples composition 2 is represented — by individual particles of a rounded and oval form with a size of ~ 0.5—3.5 μm, predominant — ~ 1.5—2.0 μm which are interconnected by intercrystalline layers. The microstructure of alumina ceramic samples of both compositions after firing at 1500 °C is similar and is composed of recrystallized corundum grains with a size of ~ 0.5—5.5 μm, predominant — ~ 1.5—2.0 μm, among which there are also larger α–Al2O3 grains, with a size of ~ 2—8 μm. After firing at 1580 °C the microstructure of samples is represented by a dense fine-grained structure of well-formed practically defect-free corundum grains, with a size of ~ 0.5—3.0 μm, among which grains of ~ 5—10 μm.

Influence of La2O3 Addition on Microstructure and Mechanical Properties of Al2O3 Ceramics

2019 ◽  
Vol 956 ◽  
pp. 69-77
Author(s):  
Xing Ze Ge ◽  
Qi Ge ◽  
Xing Shuo Ge ◽  
Deng Hui Ji ◽  
Ying Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Fracture Toughness ◽  
Grain Size ◽  
Flexural Strength ◽  
Grain Growth ◽  
Alumina Ceramic ◽  
Alumina Powder ◽  
Alumina Ceramics ◽  
Average Grain Size

In this paper, alumina ceramics were prepared with alumina powder and lanthanum nitrate. The influence of La2O3 on the microstructure and properties of alumina ceramics were studied. The result showed that the addition of La2O3 contributed to the mechanical property of the samples. The alumina ceramics with adding of 0.05wt% La2O3 sintered at 1490°C had the best mechanical properties. And the flexural strength, fracture toughness of the ceramics could reach 571.902MPa and 5.82MPa•m1/2，which were improved by 37.55% and 10.65% respectively compared with the alumina ceramics without La2O3. Besides, the average grain size of alumina ceramic is about 2.8μm, and the effect of inhibition on grain growth of alumina ceramics was obvious.

Sign in / Sign up

Export Citation Format

Share Document