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Ti6Al4V alloy and ZrO2 ceramic have similar application fields and complementary properties. Brazing connections can broaden the application range. When using sealing glass with good air tightness, good electrical insulation, and low connection temperature to connect, the solder is difficult to wet on the metal surface. The traditional method is to oxidize the surface of the alloy at a high temperature, but the film is not uniform and the treatment time is long. In this study, nanosecond laser surface treatment was used as a prewelding pretreatment method to form a micro-nano structure on the surface and perform oxidation treatment. It is particularly important to select the brazing process. After the laser parameters and processing times were determined, the effects of different welding temperatures and holding times on the properties of the joints were compared, and it was found that there were regular changes. Finally, it is concluded that the maximum shear strength is 46 MPa when the welding temperature is 650 °C and the holding time is 30 min. Under this process, the performance of the joint significantly improved under the dual effects of mechanical bonding and metallurgical bonding. This study provides a new idea for the connection of metal and ceramic and has reference value for the selection of the brazing process. [ABSTRACT FROM AUTHOR]

Titanium dioxide is one of the earliest materials used in memristors. It is widely studied and researched due to its advantages of the simple preparation process, high dielectric constant, wide bandgap and chemical stability. In this paper, a two-step anodization process was used to prepare the oxidized nanotubes array, which served as the foundation for fabricating Ag/TiO2/Ti memristors. The research delved into the impact of diverse oxidation voltages on the resistive performance of memristor and discussed the underlying mechanism for resultant performance. [ABSTRACT FROM AUTHOR]

Laser–MIG hybrid welding–brazing was used to weld 304 stainless steel and 6061-T6 aluminum alloy with a thickness of 2 mm. The microstructure, morphology, chemical composition and corrosion behavior of the samples after high-temperature oxidation were investigated. The results reveal that the 304/6061 dissimilar joint had a thicker intermetallic compound layer (7–8 μm) during high-temperature oxidation (HTO) treatment than the sample without HTO treatment (2–3 μm). The oxide film thickness of the 6061 side of the weld joint treated by HTO (2401 nm) increased compared to the samples (181.1 nm) without HTO treatment. Unlike other metals treated by high-temperature oxidation, the high-temperature treatment process in this paper can reduce the corrosion resistance of the base metal and dissimilar joints, and the sequence of the corrosion current density was weld (HTO) >weld>6061 (HTO) >6061>304 (HTO) >304. [ABSTRACT FROM AUTHOR]

The weather‐resistant steel S355J2W shows potential for use in the bogies of high‐speed trains operating in extremely cold regions. In this study, the mechanical properties and fracture behavior of S355J2W steel and its MAG welding joints were investigated using low‐temperature uniaxial tensile tests, Charpy impact tests, and three‐point bending tests (TPB), which play an important role in the safety and reliability of train operation. The ductility and toughness indices decreased as the temperature decreased from room temperature to −114°C, and the weld is more dangerous and prone to fracture than the base material area. The бs/бb values of WM and HAZ samples slightly increased by 3.7% and 3.8% from 20 to −114°C, respectively. And the ductile–brittle transition temperature (DBTT) of BM, WM, and HAZ were −75.6, −46.1, and −56.6°C, respectively. The fracture micro‐mechanisms were evaluated by analyzing the grain misorientation along the residual cracks using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The high‐angle grain boundaries (GBs) in the base metal were observed to greatly contribute to stopping or deflecting the crack propagation, thereby improving the low‐temperature toughness. In contrast, the cracks easily penetrate the low‐angle GBs of the weld (which made up 38% of the grain boundaries of the welds), thereby decreasing the lower temperature fracture toughness of the weld. The dislocations of S355J2W steel and the weld metal were investigated by TEM analysis. Highlights: бb, бs values of S355J2W steel, weld, and HAZ were investigated from −114 to 20°C.The DBTT of S355J2W, WZ, and HAZ were −75.6, −46.1, and −56.6°C, respectively.δm of the weld was the lowest, which means that the fracture toughness deteriorated in the weld.High‐angle grain boundaries contributed to improving the low‐temperature toughness. [ABSTRACT FROM AUTHOR]

With the development of the high-end equipment manufacturing industry, the requirements for the surface performance of critical components are likewise increasing. To control the heat and mass transfer in the laser surface treatment process more efficiently and flexibly, the multiangle double laser surface treatment technology shows unique advantages. This study is focused on the experimental study of the laser surface treatment process for Ti6Al4V material. By changing the laser power and the incidence angle of the laser beam, the effects of single-laser beam surface treatment (SLST) and dual-laser beam surface treatment (DLST) on the surface morphology of the alloy were studied. The effects of laser treatment on the surface morphology, element distribution, roughness, surface chemical state, and surface structure of the alloy were emphatically analyzed. The mechanism of SLST and DLST at different incident angles of heat source and the effect of DLST on the formation of an oxide layer on the surface of the alloy were compared and analyzed. The results show that when the average power of the high-power nanosecond pulse width laser in DLST is 100 W and the incident angle is 135°, the surface oxygen content reaches the lowest, as low as 8.31%. The secondary effect of the laser makes the alloy surface remelt again, and then the best roughness after laser processing is obtained, with a roughness value of 2.801 μm. Finally, we obtain the optimal process for laser surface treatment and conclude that DLST can significantly optimize the surface state after a high-energy laser beam action. [ABSTRACT FROM AUTHOR]