Kazan Federal University continues work on determining properties of metal alloys
A joint paper with Tomsk State University saw light in Crystals.
Department Chair Anatolii Mokshin explains, "Titanium nickelide metal alloy, in which both chemical elements—nickel and titanium—are contained in equal proportions, has unique physical properties that determine its application in a wide variety of fields. This alloy has a so-called memory effect: a part made of it is able to fully restore its original shape under certain temperature conditions. In addition, titanium nickelide alloy is biocompatible, it is not rejected by the body, so it is actively used for the manufacture of medical instruments, implants and prostheses."
There are some very stringent requirements to the quality of human body implants.
"It is necessary for it to have strictly defined strength characteristics, which must correlate with the strength characteristics of the biological tissue, such as bone tissue, into which the implant is installed. If the implant is not strong enough, it will quickly collapse, and if the strength of the implant is higher than that of the biological tissue, it will cause degradation and destruction of the tissue in which it is implanted and with which it is in contact," continues the scientist.
The ability of a material to respond in one way or another to external mechanical loads—compression, tension, or torsion—is characterized by such parameters as strength, hardness, elasticity, and plasticity.
"Porosity is a somewhat unique tool that can be used to control the overall elastic-plastic properties of a material within certain limits. For example, by introducing porosity, it is possible to very carefully reduce the strength of a metal alloy to produce a sample with lower strength compared to its monolithic counterpart," says Professor Mokshin.
Department employees, while studying titanium nickelide alloy, managed to obtain a general equation, with the help of which it is possible to determine in advance the strength characteristics of the alloy depending on how porosity is realized in it.
According to Mokshin, the important scientific results were achieved by combining experimental work with work on modeling of nonequilibrium atomistic dynamics. The experimental and test part of the experiment was performed by colleagues from Tomsk State University who have extensive experience in working with such a unique alloy as titanium nickelide.
Co-author, Associate Professor Bulat Galimzyanov comments on the uniqueness of atomistic dynamics, "This method allows us to calculate with high accuracy from first principles various physical characteristics of the material under study. Thus, we have calculated strength properties for nanoporous titanium nickelide, which allowed us to significantly supplement the experimental results obtained and obtain a general solution."
More information:
A Unified Empirical Equation for Determining the Mechanical Properties of Porous NiTi Alloy: From Nanoporosity to Microporosity
www.mdpi.com/2073-4352/13/12/1656
Provided by Kazan Federal University