[en] Dependence of temperature of antiferromagnetic phase transition on pressure was investigated by the method of measuring peculiarity on R(T) curve. It is shown that peculiarity on R(T) curve is related with transition to commensurable antiferromagnetic phase both from paramagnetic and incommensurable antiferromagnetic phase

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[en] The effects of additions of yttrium on the oxidation behavior of chromium have been investigated. Three alloy compositions, Cr-0.004Y, Cr-0.04Y, and Cr-0.2Y (wt%) were studied at 900 and 1025⁰C. The results of this investigation are presented in this paper

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[en] Short note

[en] To increase energy efficiency, new plants must operate at higher and higher temperatures. Moreover, power generation equipment continues to age and is being used far beyond its intended original design life. Some recent failures which unfortunately occurred with serious consequences have clearly illustrated that current methods for insuring safety and reliability of high temperature equipment is inadequate. Because of these concerns, an understanding of the high-temperature crack growth process is very important and has led to the following studies of the high temperature failure process. This effort summarizes the results of some recent studies which investigate the phenomenon of high temperature creep fatigue crack growth. Experimental results which detail the process of creep fatigue, analytical studies which investigate why current methods are ineffective, and finally, a new approach which is based on the T^*-integral and its ability to characterize the creep-fatigue crack growth process are discussed. The potential validity of this new predictive methodology is illustrated

[en] In ECOPETROL-ICP was carried out an evaluation of the mechanical and micro structural properties of modified 9 Cr-1 Mo alloy, ASTM A-335 Gr. P91, finding higher strength mechanical properties, allowable stresses and creep rupture strength, than the conventional 9 Cr-1 Mo alloy, ASTM A-335 Gr. P9, recommending the alloy P91 as substitute tube material in the radiation zone of the Visbreaking heater of Cartagena's refinery (furnace in revamping process). The results obtained permit a thickness reduction of radiation tubes of material P91 close to 25% and increase the internal volume tube over up 8%, which is a parameter to consider in improving productivity and efficiency process. Also would be obtained a significant savings cost in the material among 5 and 10%. Additionally, expectations of both design and remaining useful life would be seen extensively favored with this change of alloy

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[en] Measurements of the elastic constants and nonlinear acoustic properties of incommensurate spin-density wave Cr+0.16 at% Pt are reported. The observed hysteretic behaviour of the nonlinear acoustic properties in the antiferromagnetic phase is related to the effects of both volume and shear strains