Using high-pressure torsion for metal processing: Fundamentals and applications

Recent progress made in biomaterials and their clinical applications is well known. In the last five decades, great advances have been made in the field of biomaterials, including ceramics, glasses, polymers, composites, glass-ceramics and metal alloys. A variety of bioimplants are currently used in either one of the aforesaid forms. Some of these materials are designed to degrade or to be resorbed inside the body rather than removing the implant after its function is served. Many properties such as mechanical properties, non-toxicity, surface modification, degradation rate, biocompatibility, and corrosion rate and scaffold design are taken into consideration. The current review focuses on state-of-the-art biodegradable bioceramics, polymers, metal alloys and a few implants that employ bioresorbable/biodegradable materials. The essential functions, properties and their critical factors are discussed in detail, in addition to their challenges to be overcome.

https://www.mdpi.com/2079-4983/8/4/44/pdf

Biodegradable Materials and Metallic Implants-A Review.

Influence of stacking-fault energy on microstructural characteristics of ultrafine-grain copper and copper-zinc alloys

Ab initio modeling of dislocation core properties in metals and semiconductors

An overview of tailoring strain delocalization for strength-ductility synergy

Solid solution strengthening of hexagonal titanium alloys: Restoring forces and stacking faults calculated from first principles

The aim of the present work was to investigate the microstructure evolution of the nanostructured Cr/CrN multilayer coatings on titanium Ti6Al4V alloy during indentation. Five types of multilayer (Cr/CrN) × 8 coatings were deposited on Ti6Al4V titanium alloy by the PVD vacuum arc method. The coatings had the same total thickness and number of constituent layers, but differed in the thickness ratio of the Cr and CrN constituent layers (QCr/CrN parameter). The indentation measurements were performed with a Berkovich indenter at loads of 100 mN, 500 mN, and 1 N. The SEM and STEM observations were focused on the cracking behaviour in the CrN layers as well as on the microstructure changes in the ductile Cr layers. The investigations demonstrate that the applied surface treatment significantly improves the hardness of the titanium alloy. The hardness of the coatings varied in the range 10 to 35 GPa, depending on the thickness ratio of the layers. Observations performed on cross-sections through the indentation zones revealed small radial cracks, which were observed only in the CrN layers. They initiated at the interface and propagated across a given layer, to be arrested at the next interface. The STEM observations also showed microstructure changes in the Cr layers due to the accommodation of plastic deformation. The two main mechanisms of permanent deformation were observed.

Halina Garbacz

Papers

Solid solution strengthening of hexagonal titanium alloys: Restoring forces and stacking faults calculated from first principles

Failure and deformation mechanisms during indentation in nanostructured Cr/CrN multilayer coatings

Microstructure and mechanical properties of nanostructure multilayer CrN/Cr coatings on titanium alloy

Erosion resistance of the nanostructured Cr/CrN multilayer coatings on Ti6Al4V alloy

The tribological properties of nano-titanium obtained by hydrostatic extrusion