scholarly journals Исследование влияния обработки лазерными импульсами наносекундной длительности на микроструктуру и сопротивление усталости технически чистого титана

Author(s):  
Ю.Р. Колобов ◽  
С.С. Манохин ◽  
В.И. Бетехтин ◽  
А.Г. Кадомцев ◽  
М.В. Нарыкова ◽  
...  

The effect of treatment with nanosecond laser pulses on the fatigue resistance of plate samples of recrystallized (grain size of the order of 2-3 µm) commercially pure titanium (grade VT1-0) under cyclic tensile loading is studied. The results of investigations by methods of scanning and transmission electron microscopy of the microstructure of the subsurface layer of the alloy under study after exposure to nanosecond laser irradiation and subsequent fatigue tests are presented.

Author(s):  
Ю.Р. Колобов ◽  
С.С. Манохин ◽  
Г.В. Одинцова ◽  
В.И. Бетехтин ◽  
А.Г. Кадомцев ◽  
...  

The microstructure of a thin subsurface layer of VT1-0 titanium alloy samples in the initial submicrocrystalline state after exposure to nanosecond laser pulses has been studied using scanning and transmission electron microscopy (with the possibility of X-ray microanalysis).


Alloy Digest ◽  
2020 ◽  
Vol 69 (6) ◽  

Abstract UPM CP Titanium Grade 3 (UNS R50550) is an unalloyed commercially pure titanium that exhibits moderate strength (higher strength than that of Titanium Grade 2), along with excellent formability and corrosion resistance. It offers the highest ASME allowable design stress of any commercially pure grade of titanium, and can be used in continuous service up to 425 °C (800 °F) and in intermittent service up to 540 °C (1000 °F). This datasheet provides information on composition, physical properties, and elasticity. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ti-167. Producer or source: United Performance Metals.


Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 562
Author(s):  
Alexey Panin ◽  
Andrey Dmitriev ◽  
Anton Nikonov ◽  
Marina Kazachenok ◽  
Olga Perevalova ◽  
...  

Experimental and theoretical studies helped to reveal patterns of surface roughening and the microstructure refinement in the surface layer of commercial pure titanium during ultrasonic impact treatment. Applying transmission electron microscopy technique, a gradient microstructure in the surface layer of the ultrasonically treated sample, where the grain size is varied from nano- to micrometers was revealed. It was shown that the surface plastic strains of the titanium sample proceeded according to the plastic ploughing mechanism, which was accompanied by dislocation sliding, twinning, and the transformations of the microstructure and phase composition. The molecular dynamics method was applied to demonstrate the mechanism of the phase transformations associated with the formation of stacking faults, as well as the reversible displacement of atoms from their sites in the hcp lattice, causing a change in coordination numbers. The role of the electronic subsystem in the development of the strain-induced phase transformations during ultrasonic impact treatment was discussed.


2011 ◽  
Vol 674 ◽  
pp. 47-51 ◽  
Author(s):  
Krzysztof Topolski ◽  
Halina Garbacz ◽  
Wacław Pachla ◽  
Krzysztof J. Kurzydlowski

The aim of this study was to investigate the homogeneity of the bulk nanocrystalline titanium rods obtained by Hydrostatic Extrusion (HE). The investigated material was commercially pure titanium grade 2. The final products of extrusion were nanocrystalline rods with diameters of 7 and 10 mm and lengths of about 250 mm. The size and shape of the grains were examined on transverse sections using transmission electron microscopy (TEM). The grain size was determined by the average grain equivalent diameter d2. The grain size diversity was quantified in terms of the equivalent diameter coefficient of variation CV (d2). The samples for the microscopic analyses were cut from various regions of the rods i.e. top, end, centre, and from surface of the rods. In all the samples, the average grain size determined on transverse sections was about 70 nm and the nano-grains in the various regions of the rods were similar in the shape. The examinations demonstrated that the nanostructure of the extruded rods was homogeneous. This observation was confirmed by the results of microhardness measurements.


2015 ◽  
Vol 60 (3) ◽  
pp. 1895-1900 ◽  
Author(s):  
K. Dyja ◽  
W. Więckowski

Abstract An important factor in the possibility of obtaining correct drawn parts with the desired functional properties is the friction between the stamped sheet and the tool. The article discusses the impact of technological lubricants developed according to our own formulas, based on vegetable oils, on the stamping process taking into account the strain distributions in the drawn parts. Biodegradable lubricants based on rapeseed oil with an addition of stearic acid or boric acid were used. The results of the friction coefficient in a strip drawing test and the numerical analysis results of the stamping process of a spherical cap from sheet metal: aluminium 2024, commercially pure titanium Grade 2, steel 5604 in dry friction and lubrication conditions, are presented. Strain distributions and changes in the drawn part wall thickness were analysed.


2021 ◽  
Vol 15 (1) ◽  
pp. 7662-7670
Author(s):  
N. Ali ◽  
M.S. Mustapa ◽  
T. Sujitno ◽  
T.E. Putra ◽  
Husaini .

This research aims to study the behavior of monotonic and cyclic plastic deformation on commercially pure titanium which has undergone surface treatment using the nitrogen ion implantation method. The doses of 2.0×1017 ions/cm2 and the energy of 100 keV were used to implant the nitrogen ions into the CpTi. Monotonic properties tests were performed in a laboratory air and at room temperature using ASTM E8 standard specimens. Fatigue and corrosion fatigue tests were conducted in a laboratory  air and in artificial saline solutions, at room temperature using ASTM 1801-97 specimens. Tensile tests were carried out with constant displacement rate and fatigue tests were carried under fully-reversed with stress-controlled conditions with stress amplitudes 230, 240, 250, 260, 270 and 280 MPa. The results showed the material properties of monotonic behavior for CpTi and Nii-Ti; tensile strength (σu) of 497 and 539 MPa and for 0.2% offset yield strength (σy) of 385 and 440 MPa, respectively and of cyclic behavior; cyclic strength coefficient (k’) of 568.41 and 818.64 and cyclic strain hardening exponent (n’) of 0.176 and 0.215, respectively. This study has succeeded in producing useful new material properties that will contribute to the field of material science and engineering.


2018 ◽  
Vol 916 ◽  
pp. 166-169
Author(s):  
Ilhamdi ◽  
Toshifumi Kakiuchi ◽  
Hiromi Miura ◽  
Yoshihiko Uematsu

Tension-tension fatigue tests were conducted using ultrafine-grained commercially pure Titanium (Ti) plates fabricated by multi-directional forging (MDFing). The MDFed pure Ti plates with the thickness of 1 mm were developed aiming at dental implant application. The fatigue properties of MDFed pure Ti plates were superior to those of the conventional rolled pure Ti plates. The higher fatigue strengths in MDFed plates could be attributed to the much finer grains evolved by MDFing. Fatigue crack initiated from specimen surface, when number of cycles to failure was shorter than 106 cycles. In the high cycle fatigue (HCF) region, however, subsurface crack initiation with typical fish-eye feature was recognized in the MDFed pure Ti plate in spite of the thin thickness. Fractographic analyses revealed that no inclusion existed at the center of fish-eye. The subsurface crack initiation mechanism could be related to the inhomogeneity of microstructure with some coarse grains in the inner part of the plate.


2020 ◽  
Vol 35 (4-5) ◽  
pp. 500-514
Author(s):  
Haden Andrew Johnson ◽  
Randall Scott Williamson ◽  
Mary Marquart ◽  
Joel David Bumgardner ◽  
Amol V Janorkar ◽  
...  

Studies have shown ultraviolet-A (UVA) irradiation of crystalline titanium oxides leads to the production of reactive oxygen species (ROS) via a photocatalytic process. The ROS exhibit antimicrobial properties that may be of benefit in preventing bacterial attachment to implant devices. Recent studies have suggested a potential benefit of mixed anatase and rutile oxides and dopants on the photocatalytic properties of titanium oxides. The goal of this work was to compare the photocatalytic activity of different anodized commercially pure titanium grade 4 (CPTi4) surfaces. CPTi4 specimens were anodized in three mixed-acid electrolytes to create crystalline oxide surfaces that were either primarily anatase, primarily rutile, or a combination of anatase and rutile. Additionally, the primarily anatase and combination oxides incorporated some phosphorous from the phosphoric acid component in the electrolyte. The photocatalytic activity of the anodized specimens was measured using both methylene blue (MB) degradation assay and comparing the attachment of S. aureus under irradiation with UVA light of differing intensities (1 mW/cm2, 8 mW/cm2, and 23 mW/cm2). Primarily rutile oxides exhibited significantly higher levels of MB degradation after exposure to 1 mW/cm2 UVA lights. Primarily rutile specimens also had the largest reduction in bacterial attachment followed by the mixed phase specimens and the primarily anatase specimens at 1 mW/cm2 UVA lights. Phosphorous-doped, mixed phase oxides exhibited an accelerated MB degradation response during exposure to 8 mW/cm2 and 23 mW/cm2 UVA lights. All anodized and unanodized CPTi4 groups revealed similar S. aureus attachment at the two higher UVA intensities. Although MB degradation assay and the bacteria attachment assay both confirmed photocatalytic activity of the oxides formed in this study, the results of the MB degradation assay did not accurately predict the oxides performance against S. aureus.


Author(s):  
Gry Hulsart-Billström ◽  
Oscar Janson ◽  
Håkan Engqvist ◽  
Ken Welch ◽  
Jaan Hong

Abstract The release of growth factors from platelets, mediated by the coagulation and the complement system, plays an important role in the bone formation around implants. This study aimed at exploring the thromboinflammatory response of H2O2-alkali soaked commercially pure titanium grade 2 discs exposed to whole human blood, as a way to assess the bioactivity of the discs. Commercially pure titanium grade 2 discs were modified by soaking in H2O2, NaOH and Ca(OH)2. The platelet aggregation, coagulation activation and complement activation was assessed by exposing the discs to fresh whole blood from human donors. The platelet aggregation was examined by a cell counter and the coagulation and complement activation were assessed by ELISA-measurements of the concentration of thrombin-antithrombin complex, C3a and terminal complement complex. The modified surface showed a statistically significant increased platelet aggregation, coagulation activation and complement activation compared to unexposed blood. The surface also showed a statistically significant increase of coagulation activation compared to PVC. The results of this study showed that the H2O2-alkali soaked surfaces induced a thromboinflammatory response that indicates that the surfaces are bioactive.


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