EFFICIENCY OF THE NICKEL-TITANIUM ALLOY IN COMPRESSION-INTESTINAL ANASTOMOSIS

На сегодняшний день, несмотря на то, что лечение заболеваний желудочно-кишечного тракта развивается уже много лет, создание желудочно-кишечных анастомозов по-прежнему остается одной из самых сложных и длительных проблем со своими осложнениями. Очевидно, осложнения часто возникают из-за наложения швов. Основное осложнение - повреждение стенки кишечника при наложении швов. Поэтому использование специальных никель-титановых сплавов вместо швов, вероятно, станет основным решением этой острой проблемы. В связи с этим, цель нашего исследования является определение эффективности никель-титановых слитков при компрессионно кишечном анастомозе. Nowadays, despite the fact that the treatment of diseases of the gastrointestinal tract has been developing for many years, the creation of gastrointestinal anastomoses is still one of the most difficult and long-lasting problems with its complications. Obviously, complications often arise from sutures. The main complication is damage to the intestinal wall during suturing. Therefore, the use of special nickel-titanium alloys instead of welds is likely to be the main solution to this acute problem. In this regard, the purpose of our study is to determine the effectiveness of nickel-titanium ingots in compression intestinal anastomosis.

What EBSD and TKD Tell Us about the Crystallography of the Martensitic B2-B19′ Transformation in NiTi Shape Memory Alloys

The complex and intricate microstructure of B19′ martensite in shape memory nickel titanium alloys is generally explained with the Phenomenological Theory of Martensitic Crystallography (PTMC). Over the last decade, we have developed an alternative approach that supposes the existence of a “natural” parent–daughter orientation relationship (OR). As the previous TEM studies could not capture the global crystallographic characteristics of the B2→B19′ transformation required to discriminate the models, we used Electron BackScatter Diffraction (EBSD) and Transmission Kikuchi Diffraction (TKD) to investigate a polycrystalline NiTi alloy composed of B19′ martensite. The EBSD maps show the large martensite plates and reveal the coexistence of different ORs. The TKD maps permit us to image the “twins” and confirm the continuum of orientations suspected from EBSD. The results are interpreted with the alternative approach. The predominant OR in EBSD is the “natural” OR for which the dense directions and dense planes of B2 and B19′ phases are parallel—i.e., (010)B19′//(110)B2 and [101]B19′//[ 1 ¯ 11]B2. The natural OR was used to automatically reconstruct the prior parent B2 grains in the EBSD and TKD maps. From the distortion matrix associated with this OR, we calculated that the habit plane could be (1 1 ¯ 2)B2//(10 1 ¯ )B19′. The traces of these planes are in good agreement with the EBSD maps. We interpret the other ORs as “closing-gap” ORs derived from the natural OR to allow the compatibility between the distortion variants. Each of them restores a parent symmetry element between the variants that was lost by distortion but preserved by correspondence.

Innovations and recent trends in Shape Memory Alloy: a review

Smart materials are materials, which have a definite response to stimulus provided through a change in pressure, temperature and termed as shape memory alloys (SMA). In this review, the general concept of SMA’s has been discussed along with shape memory effects. Shape memory material properties depend on phase shifting phenomena, which consist of pseudoelasticity and thermoelasticity. The basic SMA such as Ni-Ti (Nickel-Titanium) alloys, Copper (Cu) based SMA, Iron (Fe) based SMA are commonly used in the industry, Ni-Ti alloys are expensive but it has good super elasticity and superior mechanical properties. Cu and Fe based are economical as compared to the Ni-Ti alloys. The various fabrication techniques and common composition of the alloys have been discussed with in detail.