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Low-dimensional yttrium oxide (Y2O3) nanostructures have garnered significant research interest due to their intriguing properties arising from the dimensional effect and the modulation of the band structure. However, the simple preparation of Y2O3 nanosheets is rarely investigated due to the inherent limitations posed by the counterpart bulk cubic or monoclinic crystal structure. Herein, the low-dimensional layered Y2O3 nanosheets are prepared by a facile route of rapid heating followed by centrifugation, in which its corresponding hydrous-chloride compound is used as the sole reagent. The formation stages of layered Y2O3 nanosheets and corresponding mechanisms are elucidated in detail. The x-ray diffraction results confirm that the intermediate product after rapid heating is yttrium oxychloride (YOCl), which converts to the single-phase Y2O3 with a 2D layered phase after centrifugation. In addition, the obtained Y2O3 nanosheets possess a direct optical bandgap of 5.49 eV, and thus may hold promise for use in electronic applications. This research provides a facile and low-cost method for the preparation of other low-dimensional nanosheets with similar structures. [ABSTRACT FROM AUTHOR]

YBa2Cu3O7-δ (YBCO) thin films were fabricated rapidly on LaMnO3/MgO/Y2O3/Al2O3/Hastelloy substrate by the self-built induction heating system. The growth rate can be more than 60 nm/s, which is much higher than the traditional Metal Organic Deposition (MOD) method. The effects of heating rate, oxygen partial pressure and growth temperature on the texture and morphology of YBCO films were studied, as well as the analysis of properties. The results of X-Ray Diffraction and Scanning Electron Microscopy demonstrated that rapid heating can effectively reduce the residual of BaCO3 particles. The faster heating rate results in a faster YBCO growth rate, easier c-axis oriented grains growth and denser morphology. Moreover, the growth temperature and atmosphere window of YBCO films were obtained in the rapid heating condition. Meanwhile, the YBCO nucleation and growth models were established. This work realized the rapid crystallization of YBCO films by induction heating system and improved understanding of the nucleation mechanism of YBCO on the flexible metal substrate with buffer layers, which is extremely attractive for the industrialization development of Fluorine Free-MOD superconducting films in the future. [ABSTRACT FROM AUTHOR]

A warm stamping process of 1 and 1.2 GPa ultra-high strength steel sheets at comparatively low temperatures using rapid resistance heating was investigated to produce high strength parts. The effects of the heating temperature and rate on mechanical and surface properties of warm-stamped parts were examined. For a rapid heat rate of 100 °C/s around a heating temperature of 300 °C, the hardness of the formed parts increased from that of the as-received sheets, and the hardness for the 1.2 GPa sheet approached that of conventional hot-stamped parts from 22MnB5 steel sheets. The increase in hardness appeared only for rapid heating, and not for slow heating using a furnace. The increase in hardness is due to the transformation of retained austenite into martensite at comparatively low temperatures using rapid resistance heating and cooling. For the comparative low heating temperature, the non-coated sheet hardly oxidised, and the galvannealed sheet having high corrosion resistance did not exhibit the exfoliation of the coating layer, whereas the springback did not improve. [ABSTRACT FROM AUTHOR]

Microstructure and mechanical properties after induction hardening have a significant effect on the wear resistance performance and lifetime of 55CrMo steel ball screw. In the paper, the dilatometric curves were recorded at the different heating rate by a Gleeble-1500D thermo-mechanical simulator to determine the effect of heating rate on the austenitizing temperature of 55CrMo steel. Heat treatment of some specimens was performed by the Gleeble-1500D thermal simulator at the different heating temperature, holding time and cooling rate to investigate the effect of induction hardening parameters on the phase transformation, microstructure and microhardness of 55CrMo steel. Microstructure of specimen was analyzed using an optical microscope and a scanning electron microscope. Volume fraction of retained austenite was measured using an x-ray diffractometer. The mechanical properties were evaluated by a microhardness tester. The results show that the austenitizing temperature of 55CrMo steel increases with the increasing heating rate. Increasing the heating temperature, holding time and cooling rate of specimen is helpful in obtaining a uniform cryptocrystalline martensite. Volume fraction of retained austenite is less as the heating temperature is in the range of 900-950 °C. In the induction hardening of 55CrMo steel, the heating temperature should be in the range of 900-1000 °C. [ABSTRACT FROM AUTHOR]

The structure and kinetics of the formation of austenite in medium-carbon steel during shortterm heating above the temperature Ac followed by accelerated cooling are analyzed. It has been shown that the abnormal formation of pearlite in steel results from the concentrational and structural inhomogeneity of austenite, as well as the presence of carbide particles in ferrite areas. [ABSTRACT FROM AUTHOR]

The vibration and transient response of rapid heating on inner surface of the functionally graded material (FGM) circular cylindrical shells with outer magnetostrictive layer is investigated and computed by using the generalized differential quadrature (GDQ) method. The effects of heat flux value, power law index value, environmental temperature value and control gain value on Terfenol-D FGM circular cylindrical shell subjected to two edges clamped condition due to the not very high temperature fluid rapidly flow into the circular cylindrical shells from one side to the end of axial length direction are analyzed. The higher amplitudes of displacement and thermal stress can be obtained under the higher rapid heat flux value. With suitable product of coil constant and control gain value can reduce the amplitudes of displacement and thermal stress into a smaller value. The displacement of Terfenol-D FGM circular cylindrical shell versus the Terfenol-D thickness is stable for all power law index values. The Terfenol-D FGM circular cylindrical shell can stand against the higher temperature of environment with some values of power law index under rapid heating. [ABSTRACT FROM AUTHOR]

Regularities of the formation of physicomechanical properties of the VT16 alloy (Ti-3.33Al-5.18Mo-4.57V, wt %) quenched after furnace and rapid heating have been established using optical microscopy, X-ray diffraction (XRD), and dynamic mechanical analysis. It has been shown that changes in the modulus of elasticity of the VT16 alloy correlate with a decrease in the volume fraction of the α phase in the structure, except for a slight increase in the modulus of elasticity (related to the presence of the ω phase) in the case when quenching temperatures of 800-825°C were used. It has been found that the use of rapid heating to the quenching temperature leads to an increase in the temperature of the alloy transition into the single-phase β state, hampers grain growth during heating for quenching at temperatures close to the polymorphic-transition temperature, and creates conditions for more efficient strengthening in the course of subsequent aging. [ABSTRACT FROM AUTHOR]

The rapid heating effects on the microstructure, texture and magnetic properties of 3% Si non-oriented electrical steel has been investigated through optical microscopy, X-ray diffraction and Epstein frame. The results show that recrystallized grains were refined with increased heating rate, caused by the nucleation rate increase, which is faster than the growth rate due to rapid hearting. With the heating rate increase, the characteristic {111} recrystallization fibre of cold-rolled steel was depressed, but the beneficial 〈001〉//RD and 〈001〉//ND fibres were significantly strengthened. Although the grain-size decreases with heating rate increasing, the optimal magnetic properties can also be obtained through the recrystallized grain-size and texture optimization by rapid heating. In this research, we find the magnetic properties optimization can be obtained when annealed with 100°C/s heating rate: the core loss ( P) decrease 13% and the magnetic induction ( B) increase 3%. [ABSTRACT FROM AUTHOR]

Shape memory alloy (SMA) actuators are very promising due to their large strain and work-output, but are considered to be very slow due to their cooling rate. In this article, we explore the capabilities of a fast one-directional actuation mode based on one-occasional rapid Joule heating of SMA elements. For this purpose, a unique experimental system has been developed that applies a high-voltage electric pulse to a detwined NiTi wire and measures the resulting displacement due to the martensite to austenite phase transformation. The electric pulse is tuned to produce variable temperature jump of up to 160°C within a risetime of few microseconds. One end of the wire is clamped while the displacement of the other end is monitored both by a laser doppler vibrometer and by an optical encoder that measures the displacement of a grating device. Analysis of experimental results reveals a dead time delay between the electric pulse and the wire’s response, which is attributed to the austenite nucleation time and which determines the limit on the fastest possible shape memory actuation. Further analysis reveals relations between the dead weight used and the average acceleration and maximal velocity obtained. In particular, the maximal velocity correlates to a constant kinetic energy delivered by the wire, which suggests a constant integrand over the stress-strain curve regardless of the dead-weight used. A comparison of actuation performances demonstrates that our actuation experiments are significantly advantageous over other fast actuation methods in almost every actuation aspect reviewed. This demonstrates the great potential of SMA for applications that require high speeds and large displacements one-occasional actuation. [ABSTRACT FROM AUTHOR]

The effects of rapid heating cyclic heat treatment on mechanical properties of a TiAl-based alloy (Ti-33Al-3Cr) were studied by means of an induction heating machine. The results show that: 1) fine fully-lamellar microstructure with colony size of about 50 µm and lamellar spacing of about 0.12 µm can be obtained; 2) the compression mechanical properties can be improved to a large extent and the best comprehensive compression mechanical properties can reach the yield stress 745 MPa, the large flow stress 1 672 MPa and the compression ratio 19.4%; and 3) the compression fracture at room temperature after induction heat treatment and aging is still typical cleavage fracture. [ABSTRACT FROM AUTHOR]

Calcium substituted lead titanate thin films have been prepared by a sol-gel method, deposited by spin-coating, and thermally treated so as to obtain a perovskite structure. Two types of thermal treatments were given, differing in the heating rate, which in conventional treatments was of some 10°C/min, and in rapid treatments >500°C/min. With rapid heating, materials are obtained in which greater polarizations are commuted and bias fields are smaller. This, together with the fact that additional (undesired) phases are not observed by X-ray diffractometry when rapid treatments are used, shows that these are to be preferred over conventional treatments. [ABSTRACT FROM AUTHOR]

A new technique of rapid heating in high-temperature thermomicroscopic analysis is suggested. The apparatus is described, the metrological features of the method and its advantages and limitations are discussed. Application of the technique to studying the behaviour of refractory Nd3S4, GaP and MoS2 compounds in the temperature range from 25 to 2500°C shown. [ABSTRACT FROM AUTHOR]

Results are provided for development and study of radio engineering heat-shielding composite materials. The main properties of composite materials of the SiO-SiO class are demonstrated, and strength and thermophysical properties are determined over the whole working temperature range. Results are presented for a study of improvement of heat-resistant materials of the SiO-SiO class. The effect of refractory oxides ZrO and CrO introduced into the material structure by means of water-soluble precursors on short-term heat resistance is shown. Comparative tests are performed for the original and modified material on heating in a high-temperature gas flame, and the results obtained are evaluated. [ABSTRACT FROM AUTHOR]