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Day‐by‐day biodegradable alloys and composites are getting more attention. Besides their competing material properties with traditional permanent implants, their harmless degradation in the body eliminates the need for a second surgery to remove the implant. Beyond other biodegradable materials such as Mg and Zn, Fe is known with high strength with low degradation rate. However there is still need to improve its biocompatibility. Herein, a Fe‐based composite is developed via solid‐state manufacturing route. 10% HA/β‐TCP is selected as an additive which is a biocompatible ceramic material and the powder mix is ball‐milled. Afterward, the powders are consolidated via high‐pressure torsion (HPT) with 1–5–10 revolutions at room temperature. Crack‐free structures are obtained even after 1 HTP rotation. Fe is in lamellar form around HA‐βTCP particles. With the increase of HPT rotation numbers, lath thickness decreased. After 10 HPT rotations, 24% enhancement in density is observed that points to a more condensed structure. Transmission electron microscopy observations show significant grain refinement after 1 HPT rotation, and Fe grain size remains constant (≈300 nm) up to 10 turns. Ultimate tensile strength increases while degradation rate decreases after 5 HPT rotations. This study provides the potential of enhanced Fe‐based biomaterials for thinner and smaller implant designs. [ABSTRACT FROM AUTHOR]

Two different processing routes are used to investigate the microstructure and strength of commercial purity (CP) titanium of grade 4 processed by equal‐channel angular pressing (ECAP). In the combined temperature (CT) route, the specimens are pressed at 723 K in the first pass and at 373 K in the second pass, but in the warm temperature (WT) route, the specimens are pressed through two passes at 723 K. Both routes lead to an inhomogeneous microstructure with an average grain size of ≈1.5 and ≈1.7 μm after the CT and WT routes, respectively. Both routes give improved strengthening and higher hardness, but the CT route with a lower temperature step gives the highest ultimate tensile strength of ≈790 MPa. The inclusion of a lower temperature processing step may be important for optimizing the strength of CP Ti for the use in medical implants. [ABSTRACT FROM AUTHOR]

The aim of the study is to demonstrate the impact of high hydrostatic pressure annealing on the grain boundary character, precipitation rate, and susceptibility to intergranular corrosion of nanostructured austenitic stainless steel 316LVM. To this end, samples of an austenitic stainless steel are deformed by high pressure torsion and subsequently annealed at 900 °C for 10 min under a pressure of 2, 6 GPa and, for comparison, under atmospheric pressure. The resulting microstructures are examined using electron beam scattering diffraction, and transmission and scanning electron microscopy. It is shown that the pressure applied during annealing leads to a higher percentage of high‐angle grain boundaries than does atmospheric pressure. Moreover, it promotes the coexistence of two orientations, <111> and <100>, whereas atmospheric supports mainly <111>. High pressure hinders the growth of carbides, but drastically increases their number compared with atmospheric pressure annealing. As a consequence, the highest number of Cr23C6 carbides are present in the sample annealed under 6 GPa, making this sample susceptible to intergranular corrosion. This study demonstrates the impact of high hydrostatic pressure annealing on the grain boundary character, precipitation rate, and susceptibility to intergranular corrosion of a nanostructured austenitic stainless steel. Results show that annealing under hydrostatic pressure makes it possible to better control the microstructure transformation than conventional annealing while considering low‐angle grain boundary fraction, texture, precipitate size, and chemical composition. [ABSTRACT FROM AUTHOR]