PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 10172448

Using shape-memory alloys.

A Melzer·D Stöckel
View original source ↗Export metadata ↓

Abstract

Design considerations and material selection play important roles in the development of surgical instruments for minimally-invasive procedures. Substituting shape-memory or superelastic metals or alloys for conventional materials can lead to a significant improvement in the overall performance of those instruments. In addition, simplicity of design, a reduced number of parts, and ease of assembly and disassembly result in cost reductions.

Explore related subjects

AlloysElasticityEquipment DesignHumansMaterials TestingMinimally Invasive Surgical ProceduresSurgical InstrumentsTensile StrengthJournal ArticleReview

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

A Melzer, D Stöckel. 1995. Using shape-memory alloys.. https://pubmed.ncbi.nlm.nih.gov/10172448/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2002

On carbide dissolution in an as-cast ASTM F-75 alloy.

The solution treatment of an as-cast ASTM F-75 alloy was investigated. Microstructural evolution was followed during thermal processing, in particular with regard to the content and type of carbides formed. To evidence any probable carbide transformations occurring during the heating stage, as well as to clarify their effect on the carbide dissolution kinetics, three heating rates were studied. Image analysis and scanning electron microscopy techniques were used for microstructural characterization. For the identification of precipitates, these were electrolytically extracted from the matrix and then analyzed by X-ray diffraction. It was found that the precipitates in the as-cast alloy were constituted by both a M(23)C(6) carbide and a sigma intermetallic phase. The M(23)C(6) carbide was the only phase identified in solution-treated specimens, regardless of the heating rate employed, which indicated that this carbide dissolved directly into the matrix without being transformed first into an M(6)C carbide, as reported in the literature. It was found that the kinetics of dissolution for the M(23)C(6) carbide decreased progressively during the solution treatment, and that it was sensitive to the heating rate, decreasing whenever the latter was decreased. Because the M(23)C(6) carbide was not observed to suffer a phase transformation prior to its dissolution into the matrix, the effect of the heating rate was associated to the morphological change occurred as the specimens were heated. The occurrence of the observed phases was analyzed with the aid of phase diagrams computed for the system Co-Cr-Mo-C.

Alloys↗
PubMed2002

Preparation of TiO(2) layers on cp-Ti and Ti6Al4V by thermal and anodic oxidation and by sol-gel coating techniques and their characterization.

The excellent biocompatibility of titanium and its alloys used, for example, for medical devices, is associated with the properties of their surface oxide. For a better understanding of the tissue reaction in contact with the oxide layer, knowledge of the chemical and physical properties of this layer is of increasing interest. In this study, titania films were produced on cp-Ti and Ti6Al4V substrates by thermal oxidation, anodic oxidation, and by the sol-gel process. The thickness and structure of the films produced under different conditions were determined by ellipsometry, infrared spectroscopy, and X-ray diffraction measurements. The corrosion properties of these layers were investigated by current density-potential curves under physiological conditions. The oxide layers produced on cp-Ti and Ti6Al4V by thermal oxidation consist of TiO(2) in the rutile structure. For the anodized samples the structure of TiO(2) is a mixture of amorphous phase and anatase. The structure of the coatings produced by the sol-gel process for a constant annealing time depends on the annealing temperature, and with increasing temperature successively amorphous, anatase, and rutile structure is observed. Compared to the uncoated, polished substrate with a natural oxide layer, the corrosion resistance of cp-Ti and Ti6Al4V is increased for the samples with an oxide layer thickness of about 100 nm, independent of the oxidation procedure.

Alloys↗
PubMed2002

Static coefficient of friction between Ti-6Al-4V and PMMA for cemented hip and knee implants.

The static coefficient of friction between Ti-6Al-4V and PMMA was determined experimentally. A microtopographic surface analysis of the Ti-6Al-4V and PMMA specimens used in the experiments was performed to characterize the surfaces. The coefficient of friction between Ti-6Al-4V and PMMA in both dry and wet conditions, using both Ringer's solution and bovine serum, was determined by the standard inclined plane test, following the ASTM 4516-91 method, and by a prototype computerized sliding friction tester. The effects of surface roughness and of contact pressure on the coefficient of friction also have been investigated. Tests were performed at 26 degrees C and at body temperature of 37 degrees C. Considering all the tests, the overall range of the mean coefficients of friction varied between 0.17 and 0.32 in dry or wet conditions. For the same surface roughness in contact, in general the coefficient of friction using Ringer's solution was slightly lower than it was in dry conditions whereas bovine serum had a very high surface tension, which significantly increased the static coefficient of friction.

Alloys↗