arXiv subjects

Jan Pinc

Publications and source records attributed to Jan Pinc.

3 recordsLinked to original sources

arXiv2026

Dilute Zn alloying in biodegradable Mg wires: microstructure, mechanical performance, and degradation behavior

Dilute Mg-Zn wires are of great interest for biodegradable small-bone fixation, as magnesium degradation can support bone-related processes, while low zinc additions may provide biological benefits without compromising biocompatibility. In this work, the influence of Zn content below the room-temperature solubility limit was assessed in Mg-Zn wires intended for resorbable implant applications. Mg-0.4Zn, Mg-0.6Zn, Mg-0.8Zn, and Mg-1.5Zn alloys were processed by single-step direct hot extrusion into thin wires and characterized by correlative microstructural analysis, tensile testing, bending experiments, and in vitro degradation. All compositions achieved a recrystallized fine equiaxed grain size of 5.0-5.9 um and exhibited ultimate tensile strengths of 246-256 MPa with elongations of 23-28 %. In these thin wires, Zn content had only a limited effect on grain size, tensile properties, and bending behavior, although lower-Zn alloys showed a pronounced sharp yield point. Bending was governed mainly by extrusion texture and preserved reversible plasticity through twinning and detwinning. Simulated body fluid caused rapid localized degradation and loss of mechanical integrity within 7 days, while the biologically more relevant DMEM-based medium better reflected the expected in vivo response. Together, these findings support dilute Mg-Zn wires as a simple material platform for the development of future resorbable bone fixation devices.

cond-mat.mtrl-sci↗

arXiv2025

Effect of cold rolling strain on the microstructural evolution in equimolar MoNbTaTiZr refractory complex concentrated alloy: Comprehensive characterization

This work presents a pilot study on a strained complex concentrated alloy based on refractory elements: MoNbTaTiZr. Initially, the as-cast and homogenization-annealed conditions were characterized. After casting, the alloy consists of two solid solutions with BCC 1 and BCC 2 crystal structures. Homogenization annealing promotes the growth, ordering, and refinement of the BCC 2 phase. TEM and AES analyses indicate possible Zr segregation at grain boundaries in the as-cast state. In contrast, annealing followed by cooling results in the formation of Ti-Zr-based particles without segregation. Subsequently, the annealed alloy was cold-rolled, and its microstructure was investigated. During rolling, grain fragmentation occurs within the structure. In addition to the two BCC solid solutions, a phase with an FCC crystal structure is identified after rolling. Its composition corresponds to the Zr2Ta phase, which is a Laves phase of the A2B type. Rotational relationships, relatively rare in rolled materials with BCC structures, are identified. The texture components found after 10% rolling deformation are related to that present after 20% deformation by a 45 degrees <110> rotation, and this component is related to that appearing after 30% deformation by a 20 degrees <100> rotation. However, no distinct rolling texture or clear texture development was observed, although some mutual relationships among preferred orientations can be identified. Schmid and Taylor factor maps demonstrate that, despite deformation, the alloy remains capable of further strain accumulation and plastic deformation. Twinning is also observed after rolling, which may be beneficial, as deformation twinning contributes to improved ductility in the alloy.

cond-mat.mtrl-sci↗

arXiv2024

The influence of nitrogen ion implantation on the microstructure and chemical composition of a thin layer on the biodegradable Zn-0.8Mg-0.2Sr substrate

In this research, the influence of the N+ ion implantation process on the microstructure of a biodegradable Zn-0.8Mg-0.2Sr alloy was investigated using various experimental techniques. Microscopic analysis revealed that a fluence of 17x10^17 ions/cm^2 resulted in the oversaturation of pure Zn and Mg2Zn11 surfaces, leading to the formation of nano/micro-porous layers up to 400 nm thick. The behavior of the Zn-0.8Mg-0.2Sr alloy was observed to be similar to that of the individual pure phases, albeit without the creation of pore structures. A limited formation of MgO and Mg3N2 was observed on the alloy surface, although the overall presence of Mg significantly increased from 0.8 to 15 wt.%. This increase was caused by the decomposition of the Mg2Zn11 phase during the process and subsequent diffusion of Mg toward the surface. The absence of Zn3N2 within the samples could be explained by the thermodynamic instability and low Zn-N affinity. Despite the absence of zinc nitride, GD-OES confirmed 10 at. % of nitrogen in the pure zinc, suggesting a possible accommodation of N atoms in the interstitial positions. This study points out to the complex nature of the process and highlights other promising directions for future research.

cond-mat.mtrl-sci↗