Highly textured TiN ceramic prepared by edge-free spark plasma sintering

Highly textured Ti2AlN ceramic prepared via thermal explosion followed by edge-free spark plasma sintering

Fabrication of ZrO2-Bearing lithium-silicate glass-ceramics by pressureless sintering and spark plasma sintering

Argon gas atomized powder of Al-25mass%Si-3.5%Fe-3.5%Ni-1%Mg alloy was sintered by Spark Plasma Sintering (SPS) method. This powder and the bulk samples obtained by this sintering method were investigated by means of scanning electron microscopy, optical microscopy, X-ray diffraction and Rockwell hardness measurements. Results obtained were as follows;(1) The most of powder particles have a structure consisting of Al-Si matrix and sphere like precipitates of metastable compounds enriched in Fe and Ni. The other particles have needle like shape in the precipitates of metastable compound. This metastable compound is presumed to be Alm(m=4.4) Fe structure in which a part of Fe is substituted by Ni.(2) The Rockwell hardness of specimen sintered at 500°C by SPS method is higher than that obtained by the powder forging method. The higher hardness in the specimen procured by SPS method is attributed by the fine structure of compacts because of a completion of sintering in a short time.

Numerical modeling of changes of stress-strain state in welding of alloys of Ni-Cr–Fe alloying system at macro- and mesoscales was carried out. The kinetics of changes of stresses and deformations in the weld and heat-affected zone at sites of probable formation of hot cracks was considered. Calculations data of the stress-strain state at the macroscale were used in modeling of thermal-deformation processes at the mesoscale. During modeling the experimental data on anisotropy of physical properties were used depending on crystallographic orientation of grains in the heat affected zone of a real welded joint. The modeling was performed considering the changes of properties of the material depending on temperature. It was shown that depending on anisotropy of physical and mechanical properties of the metal in the limits of neighboring grains, the non-uniform distribution of plastic deformation becomes apparent. The change of deformation exhibits a gradient with localization of deformation near the grain boundaries.

On the structural anisotropy of physical and mechanical properties of a Bunter Sandstone

Fabrication of Ti2AlN ceramics with orientation growth behavior by the microwave sintering method

The parallel alignment of anisotropic molecules gives rise to the anisotropy of various physical properties, which is the striking feature of the liquid-crystalline state. It will be shown that there is a close relation between the anisotropy of physical properties and the molecular structure, as well as the phase structure. The anisotropy of physical properties is an essential condition for a number of practical applications besides the temperature range and the chemical stability. Therefore, the knowledge of structure-property relations is of growing interest in molecular engineering of liquid crystalline compounds with specific properties.

Ti and Ti alloys are particularly attractive materials as the metallic implant-material. This is because that these alloys have low shear modulus and the good biological compatibility with bone. However, interfacial adhesion ability of bone and Ti alloy is low. As improvement method of the interfacial adhesion ability, bioaffinity material like hydroxyapatite has been coated on surface of the Ti alloys. However, such bioaffinity materials have low strength and wear resistance. In this study, Ti composites containing biodegradable poly-L-lactic-acid (PLLA) fiber were fabricated by spark plasma sintering (SPS) method. The PLLA fiber plays a role as reinforcement in Ti matrix, and can be gradually decomposed inside body with progress of time. By the decomposition of PLLA, pore is generated in Ti matrix, and bone simultaneously penetrates into the pore. Therefore, tightly bond between bone and Ti matrix can be expected. Using the Ti-PLLA composites fabricated by SPS method, microstructural observation and mechanical tests were performed. It was found that Ti-PLLA composite has laminate-layer structure with plate-like shape PLLA. Hardness and wear behavior of Ti-PLLA composite has anisotropy due to its structure. However, strength of the Ti-PLLA composite is low because of the imperfect sintering of Ti matrix. Since sintering of Ti matrix can be improved by changing the temperature of SPS, Ti-PLLA composite with anisotropic mechanical properties can be expected by SPS method.

Effects of sintering on the microstructure and electrical properties of ZnO-based thermoelectric materials

MECHANICAL ANISOTROPY AND CRYSTALLOGRAPHIC TEXTURE IN TiAlMn ALLOY SHEET

The BaCeO3-based composite protonic conductors prepared by Spark Plasma Sintering (SPS) and free-sintering methods

SUS316L stainless steel/Inconel 718 superalloy functionally graded materials (FGMs) manufactured by directed energy deposition (DED) and powder metallurgy using spark plasma sintering (SPS) methods were investigated. The microstructures of the samples manufactured by the DED and SPS methods were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). The FGMs sample manufactured by the SPS method was found to be composed of both SUS316L stainless steel and Inconel 718 grains even in the graded zone. In contrast, in the case of FGMs manufactured by DED, mixing of the chemical composition of the raw materials in the melt pool as a result of melting forms a composition of the local region. It can be concluded that DED is effective when a precise gradient is required and the utilization of high-strength components is anticipated.

Cu2ZnSnS4 bulk polycrystalline were synthesized by pressureless sintering (PLS) method in vacuum and spark plasma sintering (SPS) method. It was confirmed that there were no the secondary phases in a sample sintered by SPS method at 750 °C from the results of powder X‐ray diffraction (XRD) patterns and Rietveld refinement. The Raman spectrum of the sample showed the strongest peak at 338 cm−1 with a shoulder at 350–370 cm−1, and the weaker peaks at about 255 and 289 cm−1, which originated from Cu2ZnSnS4. The FWHM of the strongest peak of 7.4 cm−1 was narrower than other samples. The photoluminescence (PL) spectrum measured at 15 K were observed a broad emission band with the maximum at 1.26 eV. Also, the measured photoluminescence excitation (PLE) for the band‐edge emission was originated the energy transfer from the band‐to‐band excitation.The obtained activation energy was 62 ± 9 meV.

In this study, the physical and structural properties of Mn₄Si₇ silicide crystals synthesized using Hot Isostatic Pressing (HIP) and Spark Plasma Sintering (SPS) methods were analyzed using X-ray diffraction (XRD) techniques. In the samples obtained by the HIP method, 11 diffraction peaks were identified, with crystal sizes ranging from 8.8∙10⁻⁹ m to 3.6∙10⁻⁸ m, and the lattice strain index varied from 0.01 to 0.41. These results reflect the microstructural characteristics and the deformation of the crystals, providing insight into how these structural features influence the mechanical, thermal, and electronic properties of the material. In the SPS method samples, 13 diffraction peaks were observed, with crystal sizes ranging from 3.8∙10⁻⁹ m to 3.6∙10⁻⁸ m, and lattice strain varied from 0.002 to 0.19, indicating that the crystals maintain structural equilibrium and geometric integrity. The dislocation density, measured in the HIP samples (ranging from 3.5∙101⁰ to 3.2∙1012) and SPS samples (ranging from 7.4∙1011 to 7.9∙1014), plays a crucial role in determining the crystals' plasticity and mechanical strength. The degree of crystallinity was found to be 6.4% for the HIP method and 7% for the SPS method, reflecting the structural purity and perfection of the crystals. IR transmission spectra revealed structural changes in the crystals, demonstrating their direct influence on the material's electronic and optical properties. These analyses provide valuable insights into enhancing the thermoelectric properties and mechanical stability of materials, as well as improving the performance of technological devices under high-temperature and high-pressure conditions. This study lays the foundation for future research aimed at optimizing material properties for advanced technological applications.

Sm5Fe17–based magnets, one of the newer permanent magnetic materials, were successfully produced from Sm12.5+XFe87.5-X(x = 0-17.5) melt-spun ribbons by the spark plasma sintering (SPS) method. X-ray diffraction and thermomagnetic studies revealed that the resultant Sm-Fe magnets contained the metastable Sm5Fe17 phase. From further studies, it was found that the amount of Sm5Fe17 phase and the resultant coercivity of the Sm-Fe magnets were highly dependent on the Sm content of the Sm-Fe melt-spun ribbon. The Sm22.5Fe77.5 magnet consisted of the Sm5Fe17 phase and exhibited a large coercivity of 34.2 kOe with a remanence of 46.2 emu/g (0.423T).