As interest increases in incorporating Nitinol alloys in different microapplications and devices, the development of effective procedures for laser microwelding (LMW) these alloys becomes necessary. Laser welding processes applied to Nitinol have been shown to lower strength, induce inclusions of intermetallic compounds (IMCs), and alter the pseudoelastic and shape memory effects. Inconsistency in reported weld properties has also suggested that further studies are required. The current study details the mechanical, microstructural, and phase transformation properties of Nd:YAG LMW crossed Ti-55.8 wt pct Ni Nitinol wires. The effects of surface oxide on joint performance were also investigated. Fracture strength, weld microstructure, and phase transformation temperatures at varying peak power inputs were studied and compared to the unaffected base metal. Results showed good retention of strength and pseudoelastic properties, while the fusion zone exhibited higher phase transformation temperatures, which altered the active functional properties at room temperature.

Micro and nano-joining has been identified as a key enabling technology in the construction of micromechanical and microelectronic devices. The current article reviews recent progress in micro and nano-joining. In particular, laser micro-welding (LMW) of crossed 316 LVM stainless steel (SS) wire was compared to conventional resistance microwelding (RMW) and was successfully employed in welding a Pt-Ir /SS dissimilar combination. Welding of Au nanoparticles was realized using femtosecond laser irradiation and its application in the surface enhanced Raman spectroscopy was investigated. Brazing between carbon nanotube (CNT) bundles and Ni electrodes was attained in vacuum, resulting in the development of a novel CNT filament of incandescent lamps.

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The ability to control the characteristics of scaffolds is important such that scaffolds can be fine tuned for specific applications. In this study, the effects of processing parameters on cell morphology and mechanical properties of PLGA 50/50 bioscaffolds for tissue engineering applications were investigated. Specifically, the effects of salt particle sizes and salt-to-polymer mass ratios on the scaffold relative density, average pore size and density, open-cell porosity, and mechanical properties were examined. The PLGA samples were processed using a salt leaching technique in a batch-foaming setup. Experiments showed that pore size and density were dependent on the salt particle size used, and that as the salt-to-polymer mass ratio increased, the porosity increased while the relative density decreased. The results showed that by varying the salt parameters during fabrication, the scaffold characteristics and morphology can be controlled.