Papers by Keyword: Commercially Pure Titanium

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Authors: Akira Watazu, Kay Teraoka, Hirofumi Kido, Kae Okamatsu, Yoshiyuki Nagashima, M. Morita, Masanori Matsuura, Naobumi Saito
Abstract: Commercially pure titanium thin films were uniformly formed on inner surfaces of tissue culture dishes by DC sputtering method. Then, the thickness of the film was about 30nm and the films were thin titanium oxide layer on commercially pure titanium. MC3T3-E1 cells were normally cultured on the dishes. Then, The films on the dishes were not broken and did not decompose. After 24 hours, observations of the sample from the direction of the cells' bottom surfaces adhered the titanium oxide on the commercially pure titanium film by an inverted optical microscope succeeded. Therefore, the new technique is useful for observations the interactions between titanium oxide and cells.
Authors: Qi Chao, Hossein Beladi, Ilchat Sabirov, Peter Hodgson
Abstract: The flow curve behavior and microstructure evolution of commercially pure titanium (CP-Ti) through uniaxial hot compression was investigated at 850 °C and a strain rate of 0.1/s. Electron back scattered diffraction (EBSD) was employed to characterize the microstructure and crystallographic texture development for different thermomechanical conditions. The stress-strain curves of CP-Ti alloy under hot compression displayed a typical flow behavior of metals undergoing dynamic recrystallization (DRX), which resulted in grain refinement. The critical strain for the onset of DRX was 0.13 using the double differentiation analysis technique. It was also revealed that the texture was markably altered during hot deformation.
Authors: Juan Hua Su, Ya Wei Han, Feng Zhang Ren, Zhi Qiang Chen
Abstract: The dynamic recrystallization of commercially pure titanium was investigated by compression tests on Gleeble-1500D thermal simulation test machine at temperature of 700950 °C and strain rate of 0. 015 s1. The total compression deformation is 0.7(true strain). The kinetics of dynamic recrystallization of commercially pure titanium at 950 °C was modeled by Avrami equation. The results show that the dynamic recovery and recrystallization obviously occur during compression. The flow stress increases to a peak value and gradually decreases to a steady state. The flow stress is decreased with the increase of deformation temperature and it is increased with the increase of strain rate. The Avrami kinetics model of dynamic recrystallization of commercially pure titanium at 950 °C is obtained .
Authors: Vitalii V. Larionov, Shu Peng Xu, Kun Shi, Michael X. Kroning
Abstract: The work considers the application of a magnetic spectrometer (MS) for analyzing the hydrogenation of metals (particularly, titanium and copper). Therefore, for the sake of increasing the sensitivity of the magnetic spectrometer, the following ratios are introduced: (ΔU/U)/(Δd/d) (where ΔU/U is the relative change of the MS signal and Δd/d is the relative change in the thickness of a sample), (ΔU/U)/(Δδ/δ) (where Δδ/δ is the relative change in the depth of eddy current penetration into metal) and (ΔU/U)/(ΔS/S) (where ΔS/S is the relative change in the area of sample). These parameters allow to eliminate or reduce the error in determining the conductivity value. Parameter β that is equal to the product of the sample area and the inverse value of eddy current penetration depth into metal corresponds to the effectiveness of the current penetration into metal. The authors derived a formula that ties the electric conductivity of metal to the number of implanted hydrogen atoms, which allows determining the composition of titanium hydride at different depth of metal.
Authors: Michael Battaini, Elena V. Pereloma, Chris H.J. Davies
Abstract: This paper investigates the changes in deformation mechanisms of commercially pure titanium over a range of temperatures for different orientations relative to the initial rolling texture. Samples from grade 1 titanium plate were tested in plane strain compression (PSC). Extremes of orientation relative to the predominant split basal texture were tested at temperatures from 25°C to 700°C. Specimens were subsequently examined using X-ray texture analysis and electron back-scatter diffraction (EBSD). Changing the orientation resulted in substantial yield stress anisotropy. This was found to be largely related to the orientation of the dominant texture relative to the most favorable orientation for the easiest slip mode (prism slip), and significantly but to a lesser extent on differences in twinning behaviour. The most important difference in twinning was the operation of {1012} tensile twinning in c-axis tension and {1122} compression twinning in c-axis extension. Calculations indicated that at low temperature both of these twinning modes accommodate a significant amount of strain. Twinning was also found to be the most significant factor affecting work hardening behaviour, with reorientation hardening occurring for some sample orientations. As temperature was increased above ~350°C {1011} twinning became the dominant twinning mode, but its contribution to the strain was not as large as the low temperature twinning modes, and the total amount of twinning decreased with temperature. The decrease in twinning with increasing temperature led to a reduction in the difference in work hardening behaviour. The quantitative information gathered in the course of this work is discussed in the context of mechanical property prediction.
Authors: Majid Hoseini, Philippe Bocher, Fereshteh Azari, Hojatollah Vali, Jerzy A. Szpunar
Abstract: Ultra fine grained (UFG) pure titanium fabricated by severe plastic deformation techniques has been recently considered for biomedical applications. In this study, the effects of grain size and crystallographic orientation on the biocompatibility of commercially pure titanium have been evaluated. Samples having significant differences in terms of average grain size (from 0.4 to 20 mm) and crystallographic textures have been produced using equal channel angular pressing (ECAP) and compared. X-ray diffraction and electron back scattered diffraction (EBSD) were used to document the texture and microstructural properties. Cell attachment tests were done to study the biocompatibility of the samples using MC3T3 pre-osteoblast cells. The number of attached cells was found to be higher on the samples having more (0002) plane parallel to the surface regardless of their grain sizes. It was concluded that the texture plays a more significant role than the grain size in the biocompatibility of pure titanium.
Authors: Oluwagbenga T. Johnson, Olayinka O. Awopetu, Olurotimi A. Dahunsi
Abstract: Titanium alloys are widely used in the aerospace, biotechnology, automotive, energy, marine industrial constructions and components due to their high strength-to-density ratio, excellent fatigue/crack propagation behaviour and corrosion resistance. This study investigates the αβ phase transformation which Ti-0.5Zn alloy undergoes on being subjected to heat treatment with the aim of improving its properties and to enhance its industrial application. The β phase, with Widmatansttäten type growth was produced by heat treatment of the alloy in the temperature range of 800°C to 1000°C. The resultant microstructure and hardness of the alloy was also investigated. The result showed improved morphology evidenced by transformation from the equiaxed grains to more lamellar structures in the samples. Hardness property improved by 20% too.
Authors: Song Jeng Huang, S.V. Chertovskikh, V.I. Semenov, L.Sh. Shuster
Abstract: The conditions are substantiated for the loss of thermodynamic stability of a tribosystem and for its adaptation with a decreasing wear rate at the moving frictional contact of parts from commercially pure titanium with an ultrafine-grained structure produced by equal-channel angular pressing. The regularities of the influence of the structure's dispersion degree and the friction contact's temperature on the tribotechnical characteristics of ultrafine-grained materials are established theoretically and experimentally.
Authors: Muralimohan Cheepu, V. Muthupandi, S. Loganathan
Abstract: Friction welding is a solid state joining process and it is best suited for joining dissimilar metals. It overcomes the problems associated with the conventional fusion welding processes. The joining of dissimilar metals using fusion welding processes produce brittle intermetallic precipitates at the interface which reduce the mechanical strength. Various aerospace, nuclear, chemical and cryogenic applications demand joints between titanium and stainless steel. Direct joining of these metals results in brittle intermetallics like FeTi and FexTiy, at the weld interface, which is to be avoided in order to achieve improved properties of the joints. Present study involves joining of two industrially important dissimilar metals such as commercially pure titanium and 304 stainless steel by friction welding with electroplated nickel coating as interlayer that can prevent the brittle intermetallic formation. Microstructural details of the interfaces of the friction welded joints were studied by optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) technique and X-ray diffraction (XRD). Microhardness survey was carried out across the joints and tensile test was conducted to assess the mechanical properties of the joints. Fractography studies were carried out on the fracture surfaces of the joints to know the region of failure as well as the mode of failure. XRD patterns indicate the presence of intermetallics in the friction welded joints. These two metals were successfully joined by having electroplated nickel as interlayer. The weld interface on titanium side contained Ti-Ni intermetallics layers, in which the hardness of the weld metal showing the higher value than the base metals. Fractography study conducted on the fracture surfaces created due to pull test reveals that the failure is by brittle fracture and occurred at the intermetallics layer. The maximum strength of the joints achieved for 30 μm and 50 μm thick electroplated nickel interlayers are 242 MPa and 308 MPa, respectively.
Authors: Chun Huan Chen, Rui Ming Ren
Abstract: Commercially pure Titanium (CP-Ti) TIG weld joint was treated by means of high energy shot peening (HESP) using a shot peening equipment commonly used in industry. The nanostructured surface layer was characterized by XRD, TEM, SEM and Microhardometer. The results showed that surface nanocrystallization of CP-Ti TIG weld joint were realized by high energy shot peening treatment. The finest grain size in the top surface layer is about 40nm. The hardness of the surface layer is enhanced significantly after shot peening compared with that of the as-welded joint, which resulted in a remarkable surface hardening effect. Surface welded defects such as air pores are eliminated successfully so that relative uniform surface layer was obtained.
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