Bending strength of synthetic OH-carbonated hydroxyapatite single crystals

Author(s):  
Kay Teraoka ◽  
Atsuo Ito ◽  
Kazuo Onuma ◽  
Tetsuya Tateishi ◽  
Sadao Tsutsumi
2005 ◽  
Vol 297-300 ◽  
pp. 875-880
Author(s):  
Cheol Ho Lim ◽  
Ki Tae Kim ◽  
Yong Hwan Kim ◽  
Dong Choul Cho ◽  
Young Sup Lee ◽  
...  

P-type Bi0.5Sb1.5Te3 compounds doped with 3wt% Te were fabricated by spark plasma sintering and their mechanical and thermoelectric properties were investigated. The sintered compounds with the bending strength of more than 50MPa and the figure-of-merit 2.9×10-3/K were obtained by controlling the mixing ratio of large powders (PL) and small powders (PS). Compared with the conventionally prepared single crystal thermoelectric materials, the bending strength was increased up to more than three times and the figure-of-merit Z was similar those of single crystals. It is expected that the mechanical properties could be improved by using hybrid powders without degradation of thermoelectric properties.


1972 ◽  
Vol 33 (3) ◽  
pp. 867-867
Author(s):  
Fujio Minami ◽  
Eiichi Kuramoto ◽  
Shin Takeuchi

2011 ◽  
Vol 493-494 ◽  
pp. 231-235 ◽  
Author(s):  
Mina Khorami ◽  
Saeed Hesaraki ◽  
Touradj Ebadzadeh ◽  
Sajad Farhangdoust ◽  
Ali Zamanian

Nanocrystalline carbonated hydroxyapatite was produced through hydraulic conversion of calcium phosphate cement in simulated body fluid (SBF) and then heated in a microwave oven at 1000-1250 °C. The phase composition and microstructures were evaluated, before and after the thermal processing, using XRD and SEM, respectively. Total porosity and bending strength of the samples were also tested. Proliferation and morphology of osteoblastic cells on samples were evaluated using MTT method. Limited growth of apatite crystals was observed by the thermal treatment in which the samples exhibited a crystal size of ~ 150 nm at heating temperature of 1250 º. Based on the results, the microwave irradiation led to a little change in phase composition of carbonated apatite and slight amount of β-TCP phase was found together with large amount of apatite. The sample irradiated at 1250 °C formed more dense material having bending strength value up to 130 % that of unheated sample. The in vitro cell studies showed that the microwave irradiated samples could provide adequate cell proliferation and attachment.


1998 ◽  
Vol 77 (7) ◽  
pp. 1560-1568 ◽  
Author(s):  
K. Teraoka ◽  
A. Ito ◽  
K. Maekawa ◽  
K. Onuma ◽  
T. Tateishi ◽  
...  

Author(s):  
Lucien F. Trueb

A new type of synthetic industrial diamond formed by an explosive shock process has been recently developed by the Du Pont Company. This material consists of a mixture of two basically different forms, as shown in Figure 1: relatively flat and compact aggregates of acicular crystallites, and single crystals in the form of irregular polyhedra with straight edges.Figure 2 is a high magnification micrograph typical for the fibrous aggregates; it shows that they are composed of bundles of crystallites 0.05-0.3 μ long and 0.02 μ. wide. The selected area diffraction diagram (insert in Figure 2) consists of a weak polycrystalline ring pattern and a strong texture pattern with arc reflections. The latter results from crystals having preferred orientation, which shows that in a given particle most fibrils have a similar orientation.


Author(s):  
E. L. Thomas ◽  
S. L. Sass

In polyethylene single crystals pairs of black and white lines spaced 700-3,000Å apart, parallel to the [100] and [010] directions, have been identified as microsector boundaries. A microsector is formed when the plane of chain folding changes over a small distance within a polymer crystal. In order for the different types of folds to accommodate at the boundary between the 2 fold domains, a staggering along the chain direction and a rotation of the chains in the plane of the boundary occurs. The black-white contrast from a microsector boundary can be explained in terms of these chain rotations. We demonstrate that microsectors can terminate within the crystal and interpret the observed terminal strain contrast in terms of a screw dislocation dipole model.


Author(s):  
M.P. Thomas ◽  
A.R. Waugh ◽  
M.J. Southon ◽  
Brian Ralph

It is well known that ion-induced sputtering from numerous multicomponent targets results in marked changes in surface composition (1). Preferential removal of one component results in surface enrichment in the less easily removed species. In this investigation, a time-of-flight atom-probe field-ion microscope A.P. together with X-ray photoelectron spectroscopy XPS have been used to monitor alterations in surface composition of Ni3Al single crystals under argon ion bombardment. The A.P. has been chosen for this investigation because of its ability using field evaporation to depth profile through a sputtered surface without the need for further ion sputtering. Incident ion energy and ion dose have been selected to reflect conditions widely used in surface analytical techniques for cleaning and depth-profiling of samples, typically 3keV and 1018 - 1020 ion m-2.


Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.


Author(s):  
H. P. Karnthaler ◽  
A. Korner

In f.c.c. metals slip is observed to occur generally on {111} planes. Glide dislocations on intersecting {111} planes can react with each other and form Lomer-Cottrell locks which lie along a <110> direction and are sessile since they are split on two {111} planes. Cottrell already pointed out that these dislocations could glide on {001} planes if they were not split. The first study of this phenomenon has been published recently. It is the purpose of this paper to report some interesting new details of the dislocations gliding on {001} planes in pure Ni, Cu, and Ag deformed at room temperature.Single crystals are grown with standard orientation and strained into stage II. The crystals are sliced parallel to the (001) planes. The dislocation structure is studied by TEM and the Burgers vectors ḇ and glide planes of the dislocations are determined unambiguously.In Fig.l primary P and secondary S dislocations react and form composite dislocations K.


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