bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure and Mechanical Properties of 9Cr-ODS Ferritic/Martensitic Steels by Mechanically Alloyed and Spark Plasma Sintering
Authors: Yang Jian , Guo Zhi Meng , Yang Wei Wei , Luo Ji , Chen Cun Guang
Published: March 2013

9Cr-0.35wt.%Y2O3 oxide dispersion strengthened (ODS) ferritic/martensitic steels were prepared by mechanically alloying (MA) and spark plasma sintering (SPS). FE-SEM and TEM with X-ray energy spectrum (EDX) were employed to characterize the microstructural evolution and chemical composition before and after heat treatment. The tensile properties at room temperature were also investigated by electronic tensile test. The result shows that it is mainly of equiaxed ferrite microstructure by SPS with mean grain size of about 500nm. Dispersoids about 5-20nm which are enriched in Y, Ti and O uniformly distribute in the matrix. It exhibits a high relative density, ultimate tensile strength and yield strength of 99.5%, 1554MPa and 1430MPa, respectively. The microstructures are of slender lath martensitic after 10%NaCl water solution quenching, while after tempering at 750 which change into mainly equiaxed ferritic and a little residual ferrite. The ODS steel exhibits ultimate tensile strength, yield strength and total elongation of 1198MPa, 1006MPa and 12.8% after tempering, respectively.
Stability of Microstructure and Mechanical Properties of GH984G Alloy during Long-Term Thermal Exposure
Authors: Wang Ting Ting , Wang Chang Shuai , Guo Jian Ting , Zhou Lan Zhang
Published: March 2013

A low cost Ni-Fe-based wrought superalloy for 700 advance ultra-supercritical coal-fired power plants was developed. The stability of microstructure and mechanical properties of this alloy during long-term thermal exposure was investigated by SEM,TEM and tensile tests. The experimental results showed that the major precipitates in the alloy were spherical γ, MC and discrete M23C6 distributing along grain boundary after the long-term exposure at 700 and 750 and no harmful phases, such as σ phase and η phase, were found. However, after exposure at 800 up to 3000 h, small amount of lath-like η phase precipitated at grain boundary by consuming the surrounding γ. The η phase exhibited a fixed orientation relationship with the γ matrix. During thermal exposure γ coarsened with increasing the exposure time and exposure temperature. In addition, all major phases and their stability temperature ranges were calculated by JMatPro and these results were confirmed by the experimental results. The 700 tensile tests revealed that the alloy after exposure at 700 and 750 for 3000 h exhibited excellent ductility and strength. Therefore, the GH984G alloy possessed excellent stability of microstructure and mechanical properties between 700 and 750 up to 3000 h, and it is a promising material for 700 advance ultra-supercritical coal-fired power plants.
Thermodynamic Description of the γ' Phase in the Co-Al-W Based Superalloys
Authors: Yang Shu Yu , Jiang Min , Wang Lei
Published: March 2013

The phase equilibrium and the precipitation behavior of the γ' phase in the Co-Al-W-Ni-Cr superalloys were studied by thermodynamic method. The phase equilibrium of the Co-Al-W-15Ni-5Cr alloy at 900 was calculated, and it was found that there were a γ' single-phase region and a γ+γ' two-phase region. The effects of Al/W ratio on the precipitation of the γ' phase were studied, and it was clear that higher mole fraction of the γ' phase can be obtained with the Al/W ratio of 2.5. The stability of the γ' phase can be improved by adding of Ni, as well as the servicing temperature of the Co-Al-W based superalloys. The results obtained in this work can be used for the developing of the new-type Co-based superalloys.
Influence of Phosphorus and Boron on Creep Behavior and Fracture Mechanism of GH4169 Superalloy
Authors: Tian Su Gui , Wang Xin , Liu Chen , Sun Wen Ru
Published: March 2013

By means of creep properties measurement and microstructure observation, the influence of the traces P, B on creep behaviors and fracture mechanism of GH4169 alloy was investigated. Results showed that during creep the twinning was thought to be the main deformation mechanism of GH4169 alloy, however the deformation mechanisms of alloy containing P, B were the twinning and slipping of dislocations activated within the grains. And the fact that the slipping of dislocations activated within the grain can delay the stress concentration in the local regions to restrain the initiation of the cracks to improve the creep resistance of the alloy. Compared to GH4169 alloy, the fracture of GH4169G alloy displayed the non-smooth surface. The adding traces P, B were segregated in the region near the boundary, which may promote the particle-like δ phase precipitated along the boundary to restrain the boundaries slipping and the cracks propagation. This was thought to be the main reason for enhancing the strength of the boundary and prolonging the creep life.
Effect of Mo on the High Temperature Oxidation Behavior of Co-Al-W Based Alloys
Authors: Fan Fei , Sun Hao , Zhao Di , Sha Jiang Bo
Published: March 2013

2 at.% and 4 at.% Mo were added to Co-9Al-9W-2Ta-0.02B alloy to replace W (hereafter referred to as the alloys of 2Mo and 4Mo, respectively; Mo-free alloy was referred to as the 0Mo alloy). The effects of Mo additions on the high temperature oxidation behavior of the alloys at 800 °C in air have been studied. The results indicated that, after oxidation in air at 800 °C for 100 h, the oxide film of the 0Mo alloy remained intact, but the cracking and spallation of the oxide film took place in the alloys of 2Mo and 4Mo. Oxidation kinetic curves revealed weight gain per unit area of the 0Mo alloy was 36.86 mg·cm-2, which was lower than that of the alloys of 2Mo (65.16 mg·cm-2) and 4Mo (48.54mg·cm-2). These suggested that the 0Mo alloy displayed superior oxidation resistance compared to the alloys of 2Mo and 4Mo caused by the formation of volatile MoO3 oxide, and sharp compressive stress formed in the outer layer during the oxidation. The oxide layer was composed of three layers of the Co3O4 + CoO outer layer, middle complex oxide layer containing Co, Al and W (Mo), inner Al2O3 layer and γ/Co3W zone adhere to the γ/γ' substrate.
Precipitation and Dissolution Behavior of δ Phase in Alloy GH4169G
Authors: Liu Fang , Yu Lian Xu , Chang Li Tao , Xin Xin , Zhang Wei Hong , Jia Dang , Qi Feng , Li Sheng Chao
Published: March 2013

The precipitation and dissolution behavior of δ phase at varied states including as cast, heat treated and thermal processed of GH4169G alloy, have been investigated. The results indicated that δ phase existed in the vicinity of Laves phase and carbides with mainly the rod-like, needle-like morphology, and lath-like morphology because of the segregation of Nb in the interdendritic area. The amount of the δ phase decreased with the increase of the annealing temperature, and the dissolution rate increased with the increase of the annealing temperature. After initial holding of 2 h at 1020°C, the residual δ phase fully dissolved at 1140°C for 20min for the as-cast ingot. The minimum holding time for δ phase dissolution at 1020°C was 2h.
Effects of Dy on the Microstructure and Hardness of NiAl Alloys
Authors: Zhang Zhi Yang , Guo Hong Bo , Peng Hui , Gong Sheng Kai , Xu Hui Bin
Published: March 2013

Intermetallic compound NiAl is considered as a potential candidate material for bond coat in thermal barrier coating (TBC) system due to its capability of forming a continuous and uniform alumina scale at temperatures even high than 1200 °C, but its cyclic oxidation is rather poor. Previous study has found that cyclic oxidation resistance of NiAl alloys and coatings can be drastically improved by minor Dy doping as reactive element. In this paper, NiAlDy alloys were produced by vacuum arc-melting and the effects of various Dy contents on the microstructure and hardness of NiAl alloys were investigated. The results suggest that Dy tends to segregate at grain boundaries and precipitate within grains as brittle DyNi2Al3 phase with little DyNiAl needles in it. The addition of minor Dy resulted in grain refinement. The grain size of NiAl alloy were reduced from ~1 mm to ~300 µm, with increasing the content of Dy to 0.5 at.%. The addition of ~0.1 at.% Dy caused a 10 % improvement in both the microhardness and macrohardness due to Dy solid-solution and grain-boundary segregation, but the alloy revealed decreased microhardness and macrohardness with further increasing the content of Dy to 0.5 at.% as the formation of Dy-rich phase.
Quantification and Statistical Analysis of Microstructural Features in As-Cast Ti-6Al-4V Titanium Alloy
Authors: Cheng Xiang Jun , Wu Guo Qing , Zhao Jia Qi
Published: March 2013

Based on microstructure of as-cast Ti-6Al-4V titanium alloy, an image processing to simplify model of β grain size, α lamella space was developed and a quantitative statistical method of β grain size, α lamella space in two-phase titanium alloys was established, with which β grain size and α lamella space of as-cast Ti-6Al-4V titanium alloy with different plate thickness were analyzed. The relationship between β grain size, α lamellar space and cast plate thickness was discussed. The results show that β grain size and α lamellae thickness nearly linearly increase as plate thickness increasing. β grain size has normal distribution and with cast plate thickness increasing, the dispersion gets larger.
Phase Transformation Behavior and Mechanical Properties of Ti-Mo-Sn Alloys
Authors: Chen Xiao Xue , Guo Shun , Zhao Xin Qing
Published: March 2013

A series of Ti-Mo-Sn alloys with different Mo contents from 7% to 15% (wt. %) were prepared, and the effects of Mo content and thermo-mechanical treatment on their microstructural evolution and mechanical behavior were investigated. The experimental results indicated that the β to α martensite transformation can be effectively suppressed with increasing Mo content. After cold rolling treatment, superior mechanical properties and low modulus were achieved in Ti-8Mo-4Sn alloy, with tensile strength of 1108MPa, yield strength of 1003MPa and low Youngs modulus of 53GPa. The influence of severe cold deformation on the macrostructure and mechanical properties was discussed based on the characterization of X-Ray diffraction and mechanical tests. It was demonstrated that the cold rolling induced fine α martensite and high density dislocations lead to the high strength of the Ti-Mo-Sn alloys. The fine α martensite as well as the β matrix with low stability guarantee low Youngs modulus.
Phase Transformation and Microstructure Evolution in Near-β Ti-7333 Titanium Alloy during Aging
Authors: Hui Qiong , Xue Xiang Yi , Kou Hong Chao , Lai Min Jie , Tang Bin , Li Jin Shan
Published: March 2013

A newly near-β titanium alloy Ti-7Mo-3Cr-3Nb-3Al (Ti-7333) was subjected to β phase solution treatment and ageing in the present work. The characteristics of α phase transformation in ageing treatment were studied. Results show that isothermal aging at a low temperature (350) will result in lots of ω particles with small size homogeneously distributing in the parent phase. These ω particles can act as nucleation sites for α phase and lead to the uniform precipitation of fine α phase within the β grain after further ageing treatment. However, when ageing at a higher temperature, the α phase tends to precipitate direct from the β matrix and the morphology of α phase is determined by the temperature and period of ageing treatment. After aging at 550 for 5min, acicular α phase precipitates in the β grains as well as along β grain boundaries and the size and quantity of α phase increase with the holding time. Note that Ti-7333 alloy has a quick ageing response. When aging at 700 for 1h, coarser α laths precipitate both on the grain boundary and within the grain. Increase the ageing temperature to 800, α phase precipitates within the β grain as short rod-like morphology. It is suggested that the driving force for α phase nucleation and the amount of defects in the intragranular decrease with the increasing of temperature, leading to the grain boundaries become the prior nucleation sites. Substantial α phase precipitate-free regions adjacent to β grain boundaries remained after ageing at 700 for 1h due to the rejection of β-stabilizer from coarse α lath on β grain boundaries. Aging at 800 for 1h resulted in pronounced continuous α-films along β grain boundaries.
Microstructure and Tensile Properties of 1-D Forged (TiB+TiC)/Ti Composite
Authors: Zhang Chang Jiang , Kong Fan Tao , Xiao Shu Long , Xu Li Juan , Chen Yuong , Deng Ning Jia , Ge We , Xu Guo Jun
Published: March 2013

In this work, 2.5vol. % (TiB+TiC)/Ti composite was prepared by in situ casting route then 1-D forging. The microstructure and tensile properties were presented and discussed. The results indicate that the as cast microstructure can be significantly modified by 1-D forging. After forging, TiB and TiC segregated at the prior β grain boundaries within the as-cast composite tend to fracture and align perpendicular to forging direction. Reduction in aspect ratio of reinforcements and α lath is also observed. 1-D forging can enhance the strength and elongation of as cast composite significantly. However, the increment in strength is quite limited as strain temperature increases to 700 °C. Additionally, room temperature and high temperature fracture mechanisms are also discussed.
Microstructures and Mechanical Properties of Mg Alloy FSW Joint Characterized with Asymmetric Gradient in Three Dimension
Authors: Lu Sheng , Yang Dai Li , Xiao Shi Yu , Lu Ali
Published: March 2013

Friction stir welding (FSW) experiments were carried out on AZ31 magnesium alloy under the optimized welding parameters. The temperature distribution, macrostructure and microstructure, mechanical properties of the joint were studied along three dimensions (transverse direction, longitudinal direction, thickness direction). Temperature distribution, joint appearance and microstructure demonstrate asymmetric gradient in three dimensions. The peak temperature of featured points at the welding beginning stage was lower, and the one in the ending stage was higher. The temperature of advancing side was higher than that of the retreating side. More in detail, the dynamically recrystallized microstructure in weld nugget zone (WNZ) was uniform and small. The thermomechanically affected zones (TMAZ) closed to the WNZ, which were characterized with bended and elongated grains. At advancing side, the interface between TMAZ and WNZ was very distinct. The microhardness distribution showed a typical W shape. The profile showed a slightly lower hardness in the WNZ than in the base metal,HAZ, and TMAZ correspond to the lowest one. The FSW joints were observed to fail mostly at the boundary between WNZ and TMAZ at the advancing side.
Fabrication of Lotus-Type Porous Silicon by Unidirectional Solidification in Pressurized Hydrogen Atmosphere
Authors: Yang Qian Qian , Liu Yuan , Li Yan Xiang
Published: March 2013

Lotus-type porous silicon is a promising micro-channel heat sink material in cooling of high powered electronic devices. Lotus-type porous silicon with elongated pores has been successfully fabricated by unidirectional solidification at different velocities. The average pore diameter and inter-pore spacing all increase whether along the height direction of the ingot or with increasing the thickness of graphite sheet (lower solidification velocity). The calculated porosity is in good agreement with the experimental results which almost keep as constant at different solidification velocities. The penetration ratio or the pore length increases with decreasing solidification velocity. The bigger pores are more likely to grow longer than smaller ones. In addition, the microstructure observation shows that the pores mostly distribute at the grain boundaries.
Isothermal Bainite Transformation in Aluminium Bearing TRIP Steel
Authors: Chen Peng , Xu Yun Bo , Yang Xiao Long , Yi Hong Liang , Wang Guo Dong
Published: March 2013

In this work, the bainite transformation during isothermality of aluminium bearing TRIP steel was studied by dilatometric experiment on a pushrod Formastor-F highspeed dilatometer with radio frequency induction heating. The aluminium bearing TRIP steel consisted of the microstructure of austenite, ferrite and bainite in the form of laths which produced by intercritical annealing and isothermal transformation followed by rapid cooling. The effect of intercritical annealing temperature and isothermal transformation temperature were studied by dilatometric experiment and JEOL JXA-8530F Electron Probe Microscopic Analyzer (EPMA).
Effect of Heating Temperature and Heating Rate on Austenite in the Heating Process of 300M Steel
Authors: Liu Yin Gang , Li Miao Quan , Dang Xiao Ling
Published: March 2013

The growth behavior of 300M steel was investigated on a Gleeble-3500 simulator at the heating temperatures ranging from 1273 K to 1453 K and the heating rates ranging from 0.83 K/s to 40 K/s. The grain size of austenite was measured by using SISC IAS V8.0 image analysis software on Olympus PMG3 microscope. The experimental results showed that the coarse grains of austenite occurred at the heating temperature above 1413 K and the grain size of austenite increased with the increasing of heating temperature and decreased with the increasing of heating rate. The grain boundaries of austenite became flat and the angel of grain boundaries tended to 120˚ with the increasing of heating temperature. The grain boundaries of austenite increased and changed from flat to bend with the increasing of heating rate.
Effect of Q-P-T Process on the Microstructure and Mechanical Properties of 300M Steel
Authors: Zhao Rui Wen , Liu Tian Qi , Zhao Xin Qing
Published: March 2013

The effect of Quenching-Partitioning-Tempering (Q-P-T) process on the microstructure and mechanical properties of 300M steel were investigated. X-ray diffraction, scanning electron microscopy and optical microscope were employed to characterize the evolution of microstructure as well as the volume fraction of retained austenite. The results showed that the samples treated by Q-P-T possess more retained austenite compared with traditional Quenching-Tempering process. After Q-P-T, the strength increased slightly, while the ductility and toughness improved markedly. Microstructure analysis indicated the difference between Q-T and Q-P-T process lies in the amount of the retained austenite as well as the size and size distribution of the martensite laths. The Q-T resulted in a little of thin film-like retained austenite in addition to wide martensite strip, while the Q-P-T resulted in large amount of thick-like austenite accompanying narrow martensite strip. Therefore, 300M steel with better ductility and toughness could be obtained by Q-P-T heat treatment.
Energy Saving by Applying 3000kVA Electric Arc Furnace in Fused Magnesia Production
Authors: Qi Guo Chao , Shan Feng Jun , Li Qiang , Yu Jing Yuan
Published: March 2013

Fused magnesia is an essential basic material for metal making and construction industries. Fused magnesia is usually produced with mineral arc furnace. In China, 1600 kVA arc furnaces are widely used as fused magnesia production facility. The unit power consumption for magnesia production is about 3000 kWh/t, higher than that in developed countries. In this research, a 3000 kVA new arc furnace was used to produce fused magnesia, and the unit consumption decreased to 2560kWh/t. The experimental results showed that the new furnace has good energy saving effect and market prospects.
Preparation and Heat Treatment of Ni60-WC/Cr12MoV Bimetallic Composite Materials
Authors: Cao You Qing , Lv Yu Ting , Jang Peng , Xu Jin Fu
Published: March 2013

In present work, bimetallic composite materials (BCMs) were prepared by one-step sintering in box-furnace followed by quenching in salt furnace. The morphology and mechanical properties of the fabricated BCMs were characterized systematically. The results showed that Ni60-WC/Cr12MoV BCMs with a typical transition zone of ~480 μm could be successfully prepared by sintering at 1120 °C for 15min followed by furnace cooling to 400 °C and air cooling to ambient temperature. The resultant samples were heat treated by preheating at 860 °C, heating at 1020 °C, quenching at 520 °C, and tempering for two times at 200 °C for 2h. The average micro-hardness of the BCMs was measured to be of 869.34, 755.44~413.68, and 758.02 HV, which corresponded to the parts of Ni60-WC, transition zone and Cr12MoV, respectively. The interface binding strength of the BCMs was 234.22 MPa.
A New High Order Mathematical Model for Calculating the Energy Conservation Equation
Authors: Niu Xiao Feng , Liang Wei , Hou Hua , Zhao Yu Hong , Wang Hong Xia , Xu Chun Xiang , Zhang Jin Shan , Cheng Wei Li
Published: March 2013

The Explicit Finite Difference (EFD) method is used for calculating the energy conservation equation during solidification. In order to improve the computational efficiency, the equivalent specific heat method is adopted to calculate the latent heat and the high order Alternating Direction Implicit (ADI) method is also applied, which is fourth order in space and second order in time. The degree of similarity between the simulation results and experimental results is analyzed quantitatively by the Hamming Distance (HD) for the first time, and results show that this high order mathematical model based on the equivalent specific heat method and the high order ADI method is faster and more accurate than the EFD method.
Effects of N Concentration on Electronic Structure and Optical Absorption Properties of N-Doped SrTiO3 from First Principles
Authors: Zhang Chao , Jia Yong Zhong , Jing Yan , Yao Ying , Ma Jun , Sun Jin He
Published: March 2013

The nitrogen concentration effects on electronic structures and optical properties of N-doped SrTiO3 have been investigated on the basis of density functional theory (DFT) calculations. Through band structure calculation, a direct band gap is predicted in SrTiO3-xNx. Electronic structure analysis shows that the doping N could substantially lower the band gap of SrTiO3 by the presence of an impurity state of N 2p on the upper edge of the valence band. When the doping level rises, the energy gap has little further narrowing compared with that at lower doping levels. The calculations of optical properties indicate a possible optimum N-doping level in SrTiO3 with a high photo response for visible light. These conclusions are in agreement with the recent experimental results.
The Clustering of Zn6Y9 and its Predominant Role in Long Period Stacking Order Phases in Mg-Zn-Y Alloys: A First-Principles Study
Authors: Ma Shang Yi , Liu Li Min , Wang Shao Qing
Published: March 2013

The local structures of Zn and Y in the long period stacking order (LPSO) phase in Mg-Zn-Y system were investigated by first principles calculations in details. The clustering of Zn and Y atoms ranging from single stacking fault layer to four consecutive layers was explicitly demonstrated. The calculations indicate that Zn and Y atoms prefer clustering in the form of Zn6Y9 embedding in ABCA-type building block to the random or ordered arrangements of Zn and Y atoms being enriched in two stacking fault layers. The cluster of Zn6Y9 can be regarded as the ideal stoichiometric component of LPSO and it plays a predominant role in the LPSO phases. The formation of LPSO phases is highly associated with the Zn6Y9 cluster and its derivatives.
Wear-Resistant Coatings Prepared by Combination of SHS and Lost Foam Casting
Authors: Shi Tao , Guo Zhi Meng , Gao Lin
Published: March 2013

With a brief introduction of self-propagating high-temperature synthesis (SHS) and lost foam casting (LFC), there goes an issue about the simultaneous produce of casting and wear-resistant coating by the combination of such two techniques, which has a positive significance for energy conservation and sustainable development. Through the statement of some common hard phases generated by SHS such as TiC, WC and TiB2, it indicated that the hard phases had a good combination with iron, and thus demonstrated the feasibility of the simultaneous produce of casting and wear-resistant coating. In the end, the development and the trend of the future about this issue has been drawn.
Development of ZnTe-Based Solar Cells
Authors: Tanaka Tooru , Miyabara Masaki , Saito Katsuhiko , Guo Qi Xin , Nishio Mitsuhiro , Yu Kin M. , Walukiewicz Wladek
Published: March 2013

ZnTe solar cells with homojunction and heterojunction structures have been developed. Homojunction was fabricated by thermal diffusion of Al into p-ZnTe, and the effect of the diffusion temperature on the photovoltaic (PV) properties was investigated. The highest efficiency was obtained by lowering the diffusion temperature and using p-ZnTe substrate with a low hole concentration. For the heterojunction solar cell, n-ZnO/i-ZnTe/p-ZnTe structure was fabricated, and PV properties were characterized.
Temperature Field Analysis of Directional Solidification of Multi-Crystalline Silicon
Authors: Hu Yan , Hao Hai , Liu Xiao Teng
Published: March 2013

A cost effective directional solidification (DS) technique is one of the main methods to produce multi-crystalline silicon (mc-Si) ingots for solar cells. A detailed understanding of the DS process is very important to control the formation and distribution of impurities, precipitates, thermal stress and dislocation defects in an ingot. All these factors have direct effects on the solar cells efficiency. The quality of crystal grown by DS is largely determined by the temperature field. In order to optimize the technique parameters and obtain high quality silicon ingots, the temperature fields with different heat transfer coefficients at different positions have been calculated during the silicon DS process. The influence of the heat transfer coefficients at the ingot top(ht), the ingot bottom (hb), and between ingot and crucible (hs) on the DS process of mc-Si have been analyzed. The calculation results may provide important theoretical basis for optimizing technological recipe in the productive practice.
Investigating the Effect of Vulcanization in Tread Rubber Applications
Authors: Kumar Jatinder , Singh Rupinder
Published: March 2013

Retreading has many potential applications in tyre manufacturing industry. There is a critical need for optimization of vulcanization processes used in tread manufacturing. Not much work hitherto has been reported for optimization of efficient sulphur vulcanization process of the tread manufacturing. The present experimentation work highlights approach to macro-model strength, elongation and hardness during vulcanization of rubber. Relationship between strength, elongation, hardness and other parameter has been deduced by using Taguchi L9 orthogonal array (OA). Results indicate that the hardness, elongation and strength of tread rubber while vulcanization depends significantly on the natural: synthetic rubber ratio (NR: SR), curing time and curing temperature of the rubber.
Electric Discharge Machining of 10 vol% Al2O3/Al Metal Matrix Composite - An Experimental Study
Authors: Sidhu Sarabjeet Singh , Kumar Sanjeev , Batish Ajay
Published: March 2013

The particle reinforced metal matrix composite have hard particles dispersed in matrix which make them difficult to machine with conventional machining methods. Electric discharge machining (EDM) is an effective tool for machining such materials. This experimental study was undertaken to identify the significant factors that affect the output responses while machining of 10 vol%Al2O3/Al composite material. The material removal rate (MRR) and tool wear rate (TWR) have a direct relationship with current and an inverse relationship with pulse on-time. Appropriate levels of current and pulse on time levels can be chosen while roughing and finishing operations. Normal polarity between terminals had higher MRR than with reverse polarity. The recast layer had a non-uniform and wave-like morphology and cracks penetrated into the matrix phase resulting in high residual stresses exceeding the ultimate tensile strength of the material. Pulse on-time has greater influence on recast layer thickness than current. The reinforced particles were all clustered under the machined surface with very few in the recast layer which results in a low strength of the machined surface. The presence of reinforced particles in recast layer is very rare, so it is desirable to remove it. Keywords: electro-discharge, machining, aluminum matrix composites, material, removal, tool, wear, roughness, recast, layer
Concept of Measurements and Acquisition System for Identification Process of a Synchronous Ship Generator
Authors: Polak Adam
Published: March 2013

The process of identification of the parameters of a mathematical model of any dynamic real object necessitates performing the relevant number of measurements with the accurate precision of the quantities that characterize the current temporal state of this object (i.e. object’s vector of state). The accurate identification of the parameters of such a model is achievable only with the help of an especially designed system of acquisition and measurement. This article describes the mathematical model of ship’s synchronous generator with the presupposed simplifications, the parameters of this model and the methods of its determining. There is also presented the conception of the system of acquisition and measurement (based on CompactDAQ platform produced by National Instruments), which is indispensable for identifying the parameters of this model.
Fuzzy Track-Keeping Steering Design for a Precise Control of the Ship
Authors: Małecki Józef
Published: March 2013

In this paper we design the fuzzy logic autopilot to precise control and a track-keeping control of the ship. Precise control of ship has known an increasing interest in the last years. The main benefits of usage of autopilot for control of ship can be removing a man from the dangers of the undersea environment and reduction in cost of exploration of deep seas. Currently, it is common to use the special ship to accomplish missions as the inspection of coastal and off-shore structures, cable maintenance, as well as hydrographical surveys. In the military field they are employed in such tasks as surveillance, intelligence gathering, torpedo recovery and mine counter measures. Hence, a problem of its ability to move along a reference path and keep a desired orientation is regarded. A non-linear mathematical model describes the vehicle’s dynamics. Command signals are generated by an autopilot with fuzzy control law implemented. Some results of computer simulations are provided to demonstrate effectiveness, correctness and usefulness of the approach.
Damage and Corrosion Diagnostics of Welded Light Alloys Ship Constructions
Authors: Jurczak Wojciech
Published: March 2013

Applying diagnostics consisting in evaluation of deformation based on corrosion potential measurements it is possible to extend lifetime of technical structures and make them safe for people and environment. Development of anticorrosion techniques and staff training is a fundamental requirement for safe exploitation of technical structures made of 7xxx aluminum alloys. Corrosive marine environment enforces engineers and technicians to implement advanced anticorrosion methods to make life on ship much safer. The paper presents selected problems connected with safety of exploitation of welded constructions made from 7020 and 7020M alloys in marine environment and a new method of corrosion diagnostics. Mechanical properties of the welded joints made from different kinds of binder have been determined. Corrosion resistance of these joints without anticorrosion protection has been investigated in seawater environment.
Segmentation Algorithm Using Method of Edge Detection
Authors: Żak Bogdan , Hożyń Stanisław
Published: March 2013

This paper attempts to develop a segmentation algorithm applicable to the issue of recognizing objects in video images. The paper presents the steps of the algorithm with a discussion of techniques used in mathematical morphology, filtration and gradient methods. Also there were presented examples of the results of a verification researches.
Impact Modeling of Underwater Explosion
Authors: Grządziela Andrzej , Szturomski Bogdan
Published: March 2013

Ship shock tests have been conducted for shock qualification of hull integrity and proper operation systems and subsystems. The ship shock trial identifies design and construction and it also validates shock hardening criteria. The main problem is that ship shock trials are costly. Numerical modeling and simulation, using FEM, may provide information to look into the details of fluid model, dynamic characteristics of ship hull and its internal component. The ship shock modeling and simulation has been performed and the predicted results were compared with ship shock test data made into sea trials. The preliminary studies of shock analysis approach are presented and the important parameters are discussed
The Radar Data Transmission to Computer Support System of Ship Safety
Authors: Lisowski Józef , Lazarowska Agnieszka
Published: March 2013

The radar system with automatic radar plotting aid constitutes a source of input data for algorithm determining safe trajectory of a ship. The article introduces radar data transmission details. It also presents the application of computer decision support system in collision situations of passage with greater quantity of met objects on board research and training ship m/v HORYZONT II. The system enables navigational data transmission from radar system and automatic determining of safe manoeuvre or safe trajectory of a ship. Computer programme used for communication with ARPA system was designed in Matlab software.
Quantitative Characterization of Microstructure of Ti-47Al-2W-0.5Si Alloy after Melting in Vacuum Induction Furnace
Authors: Szkliniarz Wojciech , Szkliniarz Agnieszka
Published: March 2013

In this paper, the microstructural characteristics of cast TiAl-based intermetallic alloy were conducted, indicating the average grain diameter and interlamellar spacing as the parameters that determine their functional properties. The possibilities of forming these parameters by changing the crystallisation conditions were also shown. Methods for acquisition of images as well as detection of grain boundaries and lamellar precipitations of phases, necessary in the measurement of stereological parameters of the microstructure of these alloys, were presented
Detection of Intermetallic Compounds in a Mg-5Al-3Ca-0.7Sr-0.2Mn Magnesium Alloy
Authors: Rzychoń Tomasz , Szala Janusz , Kukiełka Tomasz
Published: March 2013

In this paper the results of microstructural investigations and methodology of detection of intermetallic compounds were reported. The microstructural investigations included the light microscopy, scanning electron microscopy, chemical microanalysis and X-ray diffraction analysis. It was found that the microstructure of Mg-5Al-3Ca-0.7Sr-0.2Mn alloy consists of α-Mg, (Mg,Al)2Ca, Al3Mg13(Sr,Ca), Mg2Ca and Al2Ca intermetallic phases. The correct detection of these phases requires the high magnifications and a large number of measurements fields.
The Procedure for Quantitative Analysis of Welded Joints in QE22 Alloy
Authors: Adamiec Janusz , Młodzieniak Mateusz , Kiełbus Andrzej
Published: March 2013

The work presents the procedure for a quantitative description of the structure of a welded joint of QE22 alloy, welded with TIG method. The developed procedure includes a sampling strategy, methodology of revealing the structure and a set of image conversions necessary to conduct the quantitative assessment. One been observed a repeated fragmentation of the a(Mg) grain and fragmentation of the eutectic areas in the fusion weld, compared to the post-casting material. It results from the conditions of the fusion weld crystallization. The statistical analysis has shown that the developed procedure ensures repeatable and clear presentation of the structure of the QE22 alloy welded joint.
Transformations of Phases in Titanium Alloy after High Temperature Hydrogen Treatment
Authors: Sozańska Maria
Published: March 2013

Positive nature of the effects of hydrogen on the properties of titanium alloys is manifested in the high temperature hydrogen treatment (HTM - Hydrogen Treatment of Materials), where hydrogen is temporary alloying component. The paper presents the results of the possibilities of hydrogen using as a temporary alloying element in Ti-6Al-4V alloy and titanium Grade 3. Treatment of hydrogen alloy consisted of three stages: hydrogenation in hydrogen gas atmosphere at 650°C, a cyclic hydrogen-treatment (3 cycles 850 °C to 250 °C) and a dehydrogenation in vacuum (550°C). It was shown that hydrogen affects appreciably changes the microstructure of surface layer of the tested titanium alloy. The aim of this work is to determine the effect of hydrogen on the two-phase microstructure in Ti-6Al-4V alloy and Grade 3 titanium and hardness after high temperature hydrogen treatment.
Effect of Cooling Rate on the Porosity of the ZnAl22Cu3 Alloy
Authors: Michalik Rafał , Woźnica Henryk , Tomaszewska Agnieszka
Published: March 2013

Zn-Al-Cu alloys are characterized by advantageous set of functional quality futures: tribological, strength, corrosion. They are used as an alternative material for bronze, cast iron and aluminum alloys in bearings and as a structural material. Properties of Zn-Al-Cu can be improved by partial or total replacement of copper with silicon and addition of rare - earth elements. Previous studies of the current authors have shown a significant effect of cooling rate on the structure of the ZnAl22Cu3 alloy. The presence of pores and significant differences in porosity between samples slowly and fast cooled has been found. The aim of this study was to determine the effect of cooling conditions on the pore formation in ZnAl22Cu3 alloy. The article presents the structure of the slowly and fast cooled alloy. Structural examinations were carried out on samples taken from the top, center and bottom of the ingot. In order to determine the microstructure metallographic tests were carried out using optical microscope and electron scanning microscope. Through EDS X-ray spectrometry quantitative analysis of characteristic microareas was performed as well. In order to assess the morphological characteristics of the pore a computer program Met-Ilo developed in the Department of Materials Science, Silesian University of Technology has been used. Changes of the volume fraction and the average area on a flat cross section in particular areas of the ingot were analyzed quantitatively.
Effect of Modification of Rare Earth Elements on the Morphology of Silicon Precipitates in the ZnAl40Cu3Si Alloy
Authors: Michalik Rafał , Tomaszewska Agnieszka , Woźnica Henryk
Published: March 2013

Properties of the alloys Zn-Al-Cu can be improved by partial or total replacement of copper with silicon. The previous studies of the current authors have shown that in alloys with silicon addition its precipitates are not evenly distributed. This can lead to uneven wear of parts made of the Zn-Al-Cu alloy. The study of phenomena occurring during the crystallization of the ZnAl40Cu3Si alloy with ATD methods have shown that silicon does not form compounds and solid solutions with Zn and Al. In the examined alloy silicon is released as the primary even before the actual solidification of dendrites. It is not possible to reduce the uneven distribution of precipitates through heat treatment. Therefore it is important to assure the uniform distribution of precipitates of silicon already on the crystallization stage, e.g. by addition of rare earth elements. The purpose of this study was to determine the effect of rare earth elements on the morphology of silicon precipitates in the ZnAl40Cu3Si alloy. The investigated material were alloys containing 40 wt% Al, 3 wt% Cu and 1.5 wt% Si (Zn - remaining). The samples have been taken from the top, middle and bottom of the ingot. In order to determine the morphological characteristics of silicon precipitates a computer program Met-Ilo developed in the Department of Materials Science, Silesian University of Technology was used. Changes of the volume fraction and shape of precipitates in particular areas of the ingot were the subject of analysis in this work.
The Influence of Turbine Blade Geometry and Process Parameters on the Structure of Zr Modified Aluminide Coatings Deposited by CVD Method on the ZS6K Nickel Superalloy
Authors: Góral Marek , Pytel Maciej , Filip Ryszard , Sieniawski Jan
Published: March 2013

The Zr modified aluminide coatings is an alternative concept for replacing Pt-modified aluminide bondcoat for thermal barrier coatings. In the paper the influence of process parameters on the chemical composition and the thickness of aluminide coatings will be presented. The zirconia-doped aluminide coating was deposited on turbine blades made from ZS6K nickel superalloy during the low-activity CVD process. In recent work the influence of turbine blade geometry on thickness of coating was observed. The thickest coating was observed on the trailing and leading edge on the blade cross-section. In the conducted research, the light and scanning electron microscopy were used as well as the EDS chemical composition microanalysis.
Modelling of Grain Microstructure of IN-713C Castings
Authors: Szeliga Dariusz , Kubiak Krzysztof , Burbelko Andriy A. , Cygan Rafał , Ziaja Waldemar
Published: March 2013

This paper provides an analysis of experimental research results and numerical simulation of grain microstructure of turbine blade castings made of the IN-713C nickel superalloy. The numerical simulation was carried out by applying the ProCAST program. The geometric description of model assemblies and three-dimensional ceramic mould enclosure was developed. The boundary conditions as well as the thermal and physical coefficients for alloy and ceramic shell mould were selected for simulation purposes. The parameters of nucleation law based on normal (Gaussian) distribution as well as the values of equation coefficients were established in order to determine the growth rate of dendrite tips for the IN-713C alloy, depending on the undercooling. The experimental verification of boundary conditions for numerical simulation was carried out by comparison with the results of temperature distribution measurements performed in the castings. The analysis of grain microstructure was conducted on the surface and cross-sections of castings. The forecasted grain microstructure was determined using the CAFE module (ProCAST software). The cast microstructure as well as the value of grain growth and nucleation coefficients, which were used for numerical simulation of solidification process, were experimentally verified.
3D Attitude Estimation in Indoor Environments with a Complementary Filter for the Special Orthogonal Group SO(3)
Authors: Kmiecik Marcin , Sibilski Krzysztof
Published: March 2013

This paper presents a practical implementation of a complementary filter for 3D attitude estimation in an indoor setting. The structure of the filter is chosen basing on design principles described in [. It demonstrates the basic foundations of a complementary filter and proposes a simple and concise implementation for sensor fusion of data collected using an IMU and a Hokuyo URG 04LX laser scanner. Experimental results are shown for a handheld test bed satisfactory quality of estimation.
Flight Loads of Mini UAV
Authors: Majka Andrzej
Published: March 2013

Designing and building of the unmanned aircraft, especially light and ultra light vehicles, is mainly performed using the experience gained when constructing the flying models. There have not been uniform principles of building and exploiting of the mini and micro UAV (Unmanned Aerial Vehicle) in the form of regulations similar to those for manned airplanes. The unmanned vehicles of these classes in terms of their abilities and attractive price are more frequently exploited using the same air area as manned airplanes performing missions over the inhabited areas. An urgent necessity arises to work out the norms of flight suitability of the mini and micro unmanned aerial vehicles. The work contains the analysis of suitability of the current aviation regulations to determine the requirements for the mini unmanned vehicles. The work concentrates on the phenomenon of determining the symmetrical loads from the maneuvers and the turbulence atmosphere. The result of this analysis is the Limit Maneuver Envelope, Limit Gust Envelope and Limit Combined Envelope for mini UAV. The analyzed flight states allowed selecting the so called design cases which can become a basis for determining the norms of loading of mini unmanned aerial vehicles which can constitute the beginning of the regulations for building of the unmanned aerial vehicles of this class.
Telemanipulator Control with Varying Camera Position
Authors: Podsędkowski Leszek , Wróblewski Piotr , Zawierucha Marcin
Published: March 2013

Technical University of Lodz in cooperation with the Foundation for Cardiac Surgery Development conducts research on the design and control method of Polish Robin Heart cardiosurgical robots family. One of the major problems in telemanipulation is intuitiveness of control. One of the methods to ensure it is using systems that duplicate master displacement to manipulator displacement. The selection of the proper method when it is not possible to predict what will be the position of the camera observing the work area in relation to the position of the manipulator arm is especially important. Transformations between different coordinate systems must be taken into consideration. Four methods of position copying system implementation tested on RobIn Heart cardiosurgical telemanipulator will be presented in this article. Detailed algorithms will be described and the results of tests determining the duration of certain tasks will be presented.
Conception of Arm of Medical Robot Dedicated to Application of Minimally Invasive Surgery
Authors: Trochimczuk Roman
Published: March 2013

In this article only a few aspects of designing the surgical manipulator's arm will be chosen with the consideration of the kinematic structure of mechanical actuators system together with the description of requirements and the assumption for the execution system. The conception of surgical robots arm will be presented with parallelogram mechanism which increases the rigidity of the construction along with defining of kinematics matrix which describes a forward kinematics task. The aspect of limitation of the Denavit-Hartenberg method encountered by the author during the kinematics analysis of mechanism will be discussed and the solution of this systems issue will be given in this paper.
Determination of Energy Parameters of Impact Cylinders
Authors: Zbrowski Andrzej , Jóźwik Wojciech
Published: March 2013

The aim of the examination was to determine characteristics of the dynamic movement of the impact cylinder in the function of supply pressure and capacity of the chamber of the accumulator.
Laboratory Stand of an Electromagnetic Multi-Coil Launcher for Micro Aerial Vehicles
Authors: Kondratiuk Mirosław , Gosiewski Zdzisław
Published: March 2013

In the paper we present development work on an electromagnetic launcher (EML) for micro aerial vehicles (MAVs). The requirements of controlled take-off were shortly described and main advantages and disadvantages of the commonly used rubber and pneumatic launchers were enumerated. Concept, design and construction of the magnetic coil launcher were presented. The driving coils geometry determination with using the method, which was based on finite element method (FEM) and mechanical power analyses, was proposed. Finally, construction and assembling process of the device were described. In addition, the results of preliminary laboratory tests, control issues and controller target platform were mentioned.