20^th World Congress on Materials Science and Engineering June 24-26, 2019 Vienna, Austria

Katerina Mertova is working at Comtes Company in Dobřany. She is working as a Research Scientist in the Department of Mechanical Testing. At Comtes Company they provide everything from the standard testing such as tensile, compression or bending tests, and fatigue or fracture toughness tests to specialties at the customer’s request. Her strengths are in handling responsibility, thoroughness and reliability. She focuses on biomaterials and 3D printing.

In the scope of this paper, the usage of the miniature samples and investigating using small samples is discussed. The miniature samples were used for determination of mechanical properties for titanium alloy deposited by additive manufacturing. The tensile tests on the standard and the miniature samples were provided for commonly used Ti-6-Al-4V alloy. These titanium alloy samples were produced by electron beam melting and by selective laser melting method that belongs to powder bed fusion processes of 3D printing. The purpose of this work was to demonstrate that local material characteristic can be obtained using the miniature specimen. The usage of small samples could provide many advantages for testing of mechanical properties. In our investigation it is shown that the results are in good agreement for standard and miniature specimens. The strength characteristics reached identical values. However, the plastic characteristic, such as elongation and reduction of area, are not comparable duo to the presence of internal defects. The small defects, such as lack of fusion or pores, have major impact on the miniature samples in comparison to the negligible influence on the larger specimens. The fractography included in this research reveals the differences for the small and standard size specimens.

Manuel F Azamar has completed his Bachelor's degree in Mechanical Engineering at Instituto Tecnologico de Veracruz, in 2016. He has completed an internship for one year at the Research and Development Center of Tenaris Tamsa, Veracruz, Mexico in the Departments of Materials, Metallurgy and Welding Technology analyzing the parameters of different welding processes applied to seamless steel pipes and its impact in mechanical properties. Currently he is pursuing his Postgraduation in Materials Science in the Instituto de Investigaciones en Materiales at UNAM, Mexico City, Mexico.

Metallic foam is a porous media that combines physical and mechanical properties, such as a low specific weight with high compression strength. Since pores are interconnected, foams have the capacity to conduct fluids, reason why represent an option in engineering. The objective of this research is to investigate the permeability behavior of aluminum foams with different pore sizes simulating pressure and temperature conditions of reservoir, with the aim of evaluating its performance as an alternative for oil and gas industry. The methodology followed consisted in the preparation of aluminum (Al) foam samples with different pore sizes. This was carried out by means of infiltrating an open pore bed of bonded sodium chloride (NaCl) particles with molten Al, and then leaching the NaCl in distilled water. The wall thickness among the pores was measured and porosity percentage was calculated using a helium pycnometer. The compressive behavior of the foams was determined using an instron universal testing system, for obtaining young's modulus and compression strength. Finally, with the Darcy's law, the permeability coefficient of the samples was calculated by oil flux with high pressures intervals at room temperature, 100ºC and 200ºC. The importance of this project is that metallic foams for the energy industry have never been investigated nor proposed, thus the results presented in this research give way to a new engineering application of this materials.

Athar Safari has her expertise in Materials Science and Engineering. With respect to her background on high-temperature mechanical behavior and creep properties of metallic alloys, she is dealing with the possibilities to increase the service life, hardness, heat resistance, application temperatures and damage resistance of materials used as die forging tools for high-temperature forming of Titanium Aluminides.

The isothermal forging of titanium aluminides takes place between 1100°C and 1250°C with very low strain rates. This requires materials for the forming tools which have high stability at elevated forming temperatures as well as high resistance against wear, good oxidation resistance and heat resistance. At present, forging dies made of molybdenum alloys, which enable the shaping of titanium aluminide materials in an isothermal forging process, are used. Particle-reinforced molybdenum-hafnium-carbon alloys (MHC) exhibit a sufficiently high yield strength at 1200°C and a much better heat resistance than nickel-base alloys, iron aluminides or high-strength steels. Further progress in the development of new titanium aluminide alloys requires advanced forging tools and thus more knowledge about the tool material. Despite the great potential and application technological acceptance of MHC in high temperature applications, the thermo-mechanical behavior of this alloy with special focus on alternating load is not completely understood. Considering the forging process as a high temperature long-term low cycle fatigue process, in this study the mechanical behavior of MHC was investigated after several cyclic loading patterns. The tests were performed under different stress levels and different speed conditions. Microstructural observations, using optical microscopy and secondary electron microscopy were carried out. Hardness measurements were performed before and after cyclic loading in different conditions. The results show a decrease in the number of cycles until sample failure with increasing level of applied stress and an increase in the number of cycles until failure with increasing velocity.

Gregory Lacoste has his expertise in mechanical testing of aeronautical materials and structures. He has specialized in high temperature tests for the characterization of materials evolving in extreme conditions such as turbomachinery. He is also specialized in video measurement (digital image stereo correlation and in situ image analysis).

Context of the test: The Direction Générale de l’Armement (French military direction) is a major actor of aeronautical airworthiness. One of its tasks is to ensure the ability of operational conditions of French military systems. In this context, DGA Techniques aéronautiques performed mechanical tests on elementary and technological specimens to extend the flight-life of a fighter aircraft. 278 stress specimens were tested for this qualification program, with a lifetime of 10,000 to 500,000 cycles. One kind of those specimens were made of two steel parts clamped by a carbon plate and screw fasteners. Until now, regular visual inspections were performed to detect crack ignition. Those operations were very time-consuming and they mobilized technical staff during several years for the whole campaign. Therefore, a test method was developed to automatize this inspection. Description of the adopted solution: DGA TA has developed an automated crack control system by the means of a camera and an image analysis, allowing the tests to be performed without operator (except for the set up) during days, nights and weekends. The set up includes four cameras, an analyze computer and a mechanical testing machine. A program for image processing was developed with Datalogic software. Every one thousand cycles, a picture per fastener was taken and those pictures were compared with a reference state, which is the beginning of the test. A crack criterion was defined on a given area. A difference greater than 100 pixels with respect to the initial state correspond to the crack ignition. Afterwards, a signal was sent to the machine to switch the test off. At the end, the operator visually inspected the specimen and decided to continue or terminate the test.

Aleksandra Debowska is pursuing her PhD at AGH University of Science and Technology. Currently, her area of research interest includes scientifically high temperature corrosion science and alternative energy sources. She graduated in chemistry with forensic and conservation chemistry specialization from Jagiellonian University, Cracow, Poland.

The choice of material used to work at high temperatures is one of the main problems while designing equipment for energy applications. Additionally, the presence of such elements as S, Cl, K or Na (typical elements which may be find at biomass or municipal wastes) in the work environment increases the possibility of corrosion occurrence. The aim of this study was to investigate the surface and cross-section of weld cladded (CMT, Cold Metal Transfer method) samples of Inconel 625 after exposure to different renewable fuel ashes at 650 °C for 500 h. Characterization of the Inconel samples and ashes after the corrosion process was performed using scanning electron microscopy (SEM) with EDAX analysis, X-ray fluorescence (XRF) and X-ray diffraction (XRD). Figure 1 shows cross-sectional image of Inconel sample after the corrosion process caused by mixed wood ash. On the surface, the corrosion products can be distinguished mostly oxides of elements such as chromium or nickel. Moreover some ashes compounds were observed as residues. There was proved that the effects of corrosion process depend on the type of ash used.

Remigiusz Bloniarz is pursuing his PhD at AGH University of Science and Technology. He is scientifically interested in behavior of materials under dynamic loading conditions, advanced thermo mechanical processing and manufacturing technologies. He was awarded by Honorable Mention in TMS Bladesmithing Competition student competition accompanying by TMS Annual Meeting & Exhibition in 2015.

Micro alloyed HSLA steel was subjected to advanced thermo mechanical processing. The unique combination of processing parameters and microstructural phenomena i.e., combined metal forming consisted of cold rolling and subsequent thermo mechanical rolling, recrystallization and precipitation processes during reheating allow to study the role of prior austenite morphology in the development process of ultrafine grained and bimodal microstructures. Produced in the thermo mechanical processing material was analyzed and characterized using optical metallography, Electron Back Scattered Diffraction (EBSD), Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD). The results show a clear effect of the paths of thermo mechanical treatment on microstructure development and mechanical response of produced in such a way micro-alloyed steel specimens. The investigated specimens were subjected to the compression and tension tests under quasi-static and dynamic loading conditions. In these tests a wide range of strain rate was applied to demonstrate the ability of the investigated inhomogeneous microstructures to accommodate the deformation effects under dynamic loading conditions. It has been shown that produced in the thermo mechanically processed specimens complex microstructures effectively inhibit nucleation of the stress concentrations. It was observed that the deformation energy dissipates on the interphase boundaries due to the differences in mechanical response of the microstructure components.

Mingyu Song has completed his Bachelor’s degree in the field of Chemical Engineering and started his study on graphene-based materials especially for toxic gas sensors and capacitors. He has won several competitions and won several prizes for his innovative design in engineering during his college days and also in International appropriate technology design competition. Currently, he is working on his paper about toxic gas sensor.

Graphene has been considered as a promising candidate for gas sensor since its high surface area, conductivity and sensitivity to its surroundings which are attributed to its unique 2D structure and conjugated carbon system. However, graphene should be functionalized to assign selectivity and higher response to bare graphene. On the contrary, metal oxide gas sensors have been reported as high responsive and selective sensors, but its operating temperature is usually higher than 150º C which is not suitable for our daily lives. In this regard, our research groups convert graphene oxide into nickel functionalized graphene oxide composite with Fe2O3 hollow nano-cube for toxic gas sensor at room temperature for synergistic effect of them. As prepared materials were characterized by scanning electron microscope, transmission electron microscope, X-ray diffractometer and gas sensor test system. We found that functionalized graphene oxide has better selectivity and response to formaldehyde gas among ammonia, trimethyl ammonia and formaldehyde gas. Consequently, response of as-prepared sensors is improved by adding iron oxide hollow nano cube. Also, it shows optimum annealing temperature at 300º C in terms sensor performance. The enhanced performance is attributed to the characteristics of nano cubes which have superb adsorption property and ability to prevent aggregation of graphene. Among three toxic gases, the sensor showed the highest response to formaldehyde gas.

Myeong Yeon Lee is a Chemical Engineer and has completed his Bachelor’s degree from Inha University. He has started his research on silica aerogel materials for thermal insulation. He has enthusiasm with cognizing problem, problem solving and giving profits to the people. He is pursuing his Master degree from Inha University. Currently, he is working on his paper about thermal insulation.

Silica aerogels have been regarded as an attractive material because of its properties such as high surface area, low thermal conductivity, low density and low index of refraction. In recent year, silica aerogels are being used in widespread applications. However, its properties such as powdery properties, mechanical properties make them hard to apply in industrial field. There are many researches to improve its mechanical properties such as for example, compounding with polymers, fibers, carbons, silane coupling agent and other materials. In this study, we tried to synthesized precursor consisted of polyethyleneimine (PEI) and triethoxy (3-isocyanatopropyl)silane (IPTES). After synthesizing, precursor was characterized by FT-IR, NMR. From this precursor (PEI-IPTES), we synthesized silica gel by sol-gel method. To check PEI-IPTES gel properties such as thermal stability, and thermal conductivity, Thermogravimetric analysis and thermal conductivity analyzer were used.

Modern conservation the restoration of art objects is followed by research in the field of material science. The application of diagnostic methods and reversible procedures in this field is a Zeitgeist scientific methodology, since the material of the original artwork, or a unique archaeological object, requires an exclusive approach. In this sense, the experimental works are performed on materials of the equivalent composition, with the inclusion of the chain of previous influences on objects of cultural heritage. In this paper the triangle is studied: material sciences, conservation and restoration and zeitgeist with a chain of previous influences. In this way, material science is viewed in the context of a multidisciplinary approach to heritage protection.