Heterogeneous Precipitation of the α-Phase in Ti15Mo Alloy Subjected to High Pressure Torsion

Bartha, Kristína; Stráský, Josef; Harcuba, Petr; Semenova, Irina P.; Polyakova, Veronika; Janeček, Miloš

doi:10.12693/aphyspola.134.790

Cited by 7 publications

(5 citation statements)

References 23 publications

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“…HPT straining results in the formation of a UFG structure of the Ti15Mo alloy [15,17,[29][30][31][32]. In the rudimentary stage of the HPT deformation, a twinning process takes place, which is followed by significant grain refinement [31,33,34].…”

Section: Discussionmentioning

confidence: 99%

Phase Transformations upon Ageing in Ti15Mo Alloy Subjected to Two Different Deformation Methods

Bartha

Stráský

Veverková

et al. 2021

Metals

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Ti15Mo alloy was subjected to two techniques of intensive plastic deformation, namely high pressure torsion and rotary swaging at room temperature. The imposed strain resulted in the formation of an ultrafine-grained structure in both deformed conditions. Detailed inspection of the microstructure revealed the presence of grains with a size of around 100 nm in both conditions. The microstructure after rotary swaging also contained elongated grains with a length up to 1 µm. Isothermal ageing at 400 °C and 500 °C up to 16 h was applied to both conditions to investigate the kinetics of precipitation of the α phase and the recovery of lattice defects. Positron annihilation spectroscopy indicated that the recovery of lattice defects in the β matrix had already occurred at 400 °C and, in terms of positron trapping, was partly compensated by the precipitation of incoherent α particles. At 500 °C the recovery was fully offset by the formation of incoherent α/β interfaces. Contrary to common coarse-grained material, in which the α phase precipitates in the form of lamellae, precipitation of small and equiaxed α particles occurred in the deformed condition. A refined two-phase equiaxed microstructure with α particles and β grain sizes below 1 μm is achievable by simple rotary swaging followed by ageing.

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Section: Discussionmentioning

confidence: 99%

Phase Transformations upon Ageing in Ti15Mo Alloy Subjected to Two Different Deformation Methods

Bartha

Stráský

Veverková

et al. 2021

Metals

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“…In initial powder sintered at 800 • C and 850 • C and in milled powder sintered at 850 • C, α-phase precipitated during cooling. High imposed strain in the milled powder provides preferential nucleation sites (dislocations and grain boundaries) for α-phase nucleation and enhances the diffusion promoting the growth of α-phase precipitates [34]. Both these effects-the higher contamination by oxygen and enhanced precipitation of α-phase due to milling-explain the higher amount of α-phase in the sintered milled powder compared to the initial one.…”

Section: Spark Plasma Sinteringmentioning

confidence: 99%

“…As a consequence, lower sintering temperatures were therefore sufficient to obtain fully compacted material. Moreover, the milled powder was better sintered due to enhanced diffusivity in the severely deformed and refined material [34]. The dependence of the microhardness on the sintering temperature for both initial and milled powder is shown in Figure 8.…”

Section: Spark Plasma Sinteringmentioning

confidence: 99%

Mechanical Properties of Ti-15Mo Alloy Prepared by Cryogenic Milling and Spark Plasma Sintering

Veverková

Kozlík

Bartha

et al. 2019

Metals

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Metastable β-Ti alloy Ti-15Mo was prepared by cryogenic ball milling in a slurry of liquid argon. Material remained ductile even at low temperatures, which suppressed particle refinement, but promoted intensive plastic deformation of individual powder particles. Repetitive deformation of powder particles is similar to the multidirectional rolling and resembles bulk severe plastic deformation (SPD) methods. Initial and milled powders were compacted by spark plasma sintering. Sintered milled powder exhibited a refined microstructure with small β-grains and submicrometer sized α-phase precipitates. The microhardness and the yield tensile strength of the milled powder after sintering at 850 °C attained 350 HV and 1200 MPa, respectively. Low ductility of the material can be attributed to high oxygen content originating from the cryogenic milling. This pioneering work shows that cryogenic milling followed by spark plasma sintering is able to produce two-phase β-Ti alloys with refined microstructure and very high strength levels.

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“…Molybdenum exists in beta titanium in the form of displacement, which can produce smaller lattice distortion and maintain the plasticity of the alloys at the same time [2][3][4]. Ti15Mo alloy is one of the most promising biocompatible titanium alloys [5], but poor wear resistance limits its further development in the biomedical field. Generally, surface treatment methods such as coating and heat treatment can be applied to improve the tribological properties of the alloys [6].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of titanium carbide coating on Ti15Mo alloy and its tribological behaviour

Wang,

Shen,

Zhang

et al. 2023

Biosurface and Biotribology

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Ti15Mo alloy has been regarded as one of the most potential biomedical materials due to its excellent performance. However, the low hardness and poor wear resistance of titanium alloy limit the further application. Therefore, high temperature solid carburising technology was performed on the surface of Ti15Mo alloys to prepare titanium carbide (TiC) coating with graphene (G) as the carburising agent. The microstructure, mechanical properties, and tribological properties of TiC coating under different lubricants were investigated. Results showed that TiC coating was closely bonded to the titanium substrate. The maximum thickness of TiC coating treated with 1150°C was approximately 184.02 μm, and the microhardness of alloys treated with 1100°C can achieve 1221.5 HV. All modified Ti15Mo alloys showed improved tribological performance compared to the original samples. The wear mechanisms of modified Ti15Mo alloys were abrasive wear and adhesive wear under the SBF lubricant, and the TiC coating was slightly peeled off. The overall friction coefficient and wear rate under 25% calf serum lubricant were lower than the SBF lubricant, and surface scratches were almost absent, and slight abrasive wear and adhesive wear occurred on the surface.

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Heterogeneous Precipitation of the α-Phase in Ti15Mo Alloy Subjected to High Pressure Torsion

Cited by 7 publications

References 23 publications

Phase Transformations upon Ageing in Ti15Mo Alloy Subjected to Two Different Deformation Methods

Phase Transformations upon Ageing in Ti15Mo Alloy Subjected to Two Different Deformation Methods

Mechanical Properties of Ti-15Mo Alloy Prepared by Cryogenic Milling and Spark Plasma Sintering

Synthesis of titanium carbide coating on Ti15Mo alloy and its tribological behaviour

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