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The present work investigates the corrosion behavior of Al0.1CoCrFeNi high entropy alloy (HEA) in various concentrations of chloride-containing solutions. Electrochemical tests exhibit overall excellent corrosion resistance of this alloy against the attack of Cl−-containing solutions. The main type of corrosion topography presents an intergranular feature. In addition, electrochemical impedance spectroscopy (EIS) investigation of the HEA samples under immersion test suggests chloride anion–containing environment leads to the decline of passivation film quality. Further analysis of XPS results reveals that significant amounts of elements exist with atomic states in the passive films.

A Ti-based metallic glass matrix composite (MGMC), which contains abundant primary α′ and ω phases in dendrites, has a strong work-hardening ability. A significant martensitic transformation occurred during plastic deformation at 298 K, and deformation twins were produced at 77 K. Transformation-induced plasticity and twinning-induced plasticity enable MGMC to achieve prominent strength–plasticity synergy. At 298 K, the alloy exhibits a yield strength (YS) of 1140 MPa and a uniform elongation (UE) of 8.1%, while at 77 K, the YS increases to 1520 MPa, still maintaining a UE of 4.6%. The prediction models of the temperature dependent YS and martensite trigger stress [Formula: see text] in MGMC were established. The strengthening and toughening mechanisms provide a great theoretical guidance for the development of low-temperature high-performance MGMCs.

In-pipe robots provide inspection and maintenance services to various pipelines. This article proposes an algorithm to calculate the required radial variations for in-pipe robots to pass through pipeline elbows smoothly. It first gives a full overview of a robot passing through a U-shaped elbow and identifies the problem location where the radial dimension changes the most. It then presents a detailed analysis on the focused stage and deduces the algorithm. Based on the obtained algorithm, a realizing Matlab program is written to calculate all possible lengths of front and rear legs at every moment during the process. Finally, the calculation results are presented to precisely describe the track of movement, the length deformations during the whole process, and different contributions of structural variables. This article provides the design and the control of an in-pipe robot with an algorithm to calculate the lengths of its legs at every moment and to what extent the deformations of elastic legs are required.

The emergence of high entropy alloys (HEAs) has drawn extensive attention due to their special alloy design concept and excellent properties. To pave the way for their engineering applications, a prototype CoCrFeNi HEA was processed through laser welding. Sound welds without cracking, pores, lack of penetration, or precipitates were obtained. The microstructure and the deformation behavior of the weld were investigated. The fusion zone (FZ) of the weld exhibits coarse columnar grains and a relatively higher hardness than that of the base metal (BM) due to the residual stress. Although the anisotropic columnar grains in the FZ lead to the loss of ductility, the weld shows a high joint efficiency and a comparable ductility relative to the BM. The deformation during tension is facilitated by both the mechanical twins and dislocation motion. The mechanical twins play a more significant role in the FZ while the dislocation motion dominates the deformation in the BM.

Compared to its mechanical behavior at 298 K, the fracture strain of a Cu 46 Zr 46 Al 8 bulk-metallic glass is slightly increased, but the maximum strength is distinctly increased by 13.3% at 77 K. At 77 K, the serrations in the stress–strain curve disappear. Based on the calculation of the temperature rise within the shear bands and the heat conduction in the heat-affected zones, the large and instantaneous temperature rise and the rapid heat conduction are responsible for the disappearance of serrations upon shear banding.

Cu-Cr-Zr alloy belongs to precipitation-enhanced, high-strength and high-conductivity copper alloys. The volume fraction of specimen deformation was 25% and the deformation rates were 0.01~1s-1 with the deformation temperature ranged from 500°C to 800 °C at Gleeble-1500 thermal simulator. The results state that the rheological stress of Cu-Cr-Zr alloy decreases with a rising temperature at a same deformation quantity. Along with the increasement of the strain rates and the temperatures during hot deformation, the grains of Cu-Cr-Zr alloy were elongated perpendicularly to the direction of compression. When the deformation temperature was 600 °C, some of fine recrystallized grains appeared.

A Ti-based metallic-glass-matrix composite exhibits tensile softening (necking) in the supercooled liquid region, accompanied by a large tensile ductility and a fragmentation of dendrites. Subjected to high temperatures, concurrent crystallization does not occur, suggesting a good thermal stability of the glass matrix. The presence of high-volume-fractioned dendrites lowers the rheology of the viscous glass matrix at high temperatures, which results in an absence of super elongation as monolithic bulk metallic glasses (BMGs). A tensile strength of 970 MPa is higher than those of most BMGs under varying strain rates, ascribing to the retardation of softening by the dendrites.

The microstructural characterization of the Zr60.0Ti14.7Nb5.3Cu5.6Ni4.4Be10.0 bulk-metallic-glass-matrix composites is investigated using high-energy synchrotron x-ray diffraction. The convoluted diffraction-intensity distribution in the azimuthal direction is naturally yielded from the spatial arrangements of the crystalline dendrites and their amorphous matrix. We facilitate the area selection and the intensity integration of the diffraction collected from a two-dimensional detector to characterize the diffraction intensity of the amorphous matrix. The results enable us to apply the modified Williamson–Hall plots for using the peak width to study the microstrain and micromechanism of the deformation of the crystalline phase.

The microstructures of the in situ bulk-metallic-glass-matrix composites are usually controlled by changing the alloy compositions. In this paper, Zr-based bulk-metallic-glass-matrix composites containing dendrites with a fixed composition of Zr37.5Ti32.2Nb7.2Cu6.1Be17.0 are synthesized by the Bridgman solidification. The sizes and volume fractions of dendrites in the composites are controlled by adjusting the withdrawal velocities. A linear relationship between the spanning lengths of individual dendrites and the withdrawal velocities is established. Large plasticity and tensile necking can be obtained by only controlling the cooling condition.