Influence of Heat Treatments on Microstructure and Mechanical Properties of Ti–26Nb Alloy Elaborated In Situ by Laser Additive Manufacturing with Ti and Nb Mixed Powder

In the present work, a Ti–26Nb alloy was elaborated in situ by laser additive manufacturing (LAM) with Ti and Nb mixed powders. The alloys were annealed at temperatures ranging from 650 °C to 925 °C, and the effects of the annealing temperature on the microstructure and mechanical properties were investigated. It has been found that the microstructure of the as-deposited alloy obtained in the present conditions is characterized by columnar prior β grains with a relatively strong <001> fiber texture in the build direction. The as-deposited alloy exhibits extremely high strength, and its ultimate tensile strength and yield strength are about 799 MPa and 768 MPa, respectively. The annealing temperature has significant effects on the microstructure and mechanical properties of the alloys. Annealing treatment can promote the dissolution of unmelted Nb particles and eliminate the micro-segregation of Nb at the elliptical-shaped grain boundaries, while increasing the grain size of the alloy. With an increase in annealing temperature, the strength of the alloy decreases but the ductility increases. The alloy annealed at 850 °C exhibits a balance of strength and ductility

Self-Assembled Three-Dimensional Graphene-Based Aerogel with Embedded Multifarious Functional Nanoparticles and Its Excellent Photoelectrochemical Activities

Here, a graphene-based aerogel embedded with two types of functional nanoparticles shaped in a three-dimensional (3D) cylindrical architecture was prepared by a facile one-pot hydrothermal process. During the hydrothermal reaction, the uniformly dispersed TiO₂ (P25) and CdS nanoparticles were loaded on the graphene sheets, and the resulting composites were self-assembled into a 3D interconnected network. It is shown that the graphene-based hydrogel and aerogel are appropriate and robust hosts for anchoring different functional nanostructured particles. The outstanding synergistic effect of this ternary graphene-based nanocomposite aerogel is also proved by the excellent photoelectrochemical activity of the as-prepared novel nanocomposite (CdS/P25/graphene) aerogel. As a new photocatalyst, the CdS/P25/graphene aerogel exhibits enhanced light absorption, improved photocurrent, extremely efficient charge separation properties, and superior durability. These excellent properties indicate that the as-prepared CdS/P25/graphene aerogel may have a great potential application in photoelectrochemical hydrogen production from water reduction under sunlight. More importantly, in this study, a significant and pragmatic consideration of integrating multifarious functional nanoobjects into the 3D graphene-based aerogel has been clearly proposed. This could provide new insights into the preparation of functional nanocomposites and facilitate their applications in related areas