Electrical resistance is modeled as conversion of electricity to heat with scattering of axial flux of EE quanta to heat with copper and oxygen electrons. In the derived resistance equation, ...parameters related to wire substructure, current density and wire temperature are considered. Wire interatoms EE travelling paths are proposed, as well. With 0,00037 wt. % O in copper wire, ASTM quoted resistance is calculated. In absence of electric current, Rc=0, then, copper atoms, J* and oxygen atoms affect the resistance by axial current, rsp quanta flux.
On the occasion of the 80th birthday of Acad. Ilija Mamuzić for 35 years as Editor-in-chief of the journal Metalurgija, 42 years as the President of the Croatian Metallurgical Society, the goal of ...this article is to give an overview of his life and achievements. Rarely has an individual not only in Croatia but in the world had influence on his profession as I. Mamuzić his own – metallurgy. He was involved and worked in all metallurgical areas: science, profession, education, organising of Faculty or Institute, Symposiums, editing, popularisation and responsability for the profession and he is an author of the history of metallurgy on the territory of Croatia, during 6000 years. In Croatian Bibliografphy base CROSBI by registration, accepted and on print will be 925 works. By the same conditions in foreign bibliography ORCID 800 works. He participated even in the education of 47 generations students (1963–2010. He received 75 various acknowledgments etc. He is an exceptional personality as individual, scientist, pedagoge, and professional. Ilija Mamuzić has achieved plenty, not because he had or was obliged to, but because he wanted to. He didn’t work to live, but to live to work.
Intensive research into inhomogeneous deformations at the beginning of the plastic flow on different metal materials has been carried out during the last few years. Lüders bands are detected using ...methods of static tensile testing, thermography and visioplasticity with digital image correlation. This paper is a review of insights into the mechanism of formation and parameters influencing the occurrence and propagation of Lüders bands. Current knowledge indicates that there is not a full explanation of the cause of the Lüders bands formation. There are also certain differences in the way some parameters influence the occurrence of Lüders bands, primarily in different materials. Therefore, modern methods are used to explain the formation of Lüders bands.
Development of improved equation for better accuracy of calculation of stationary creep rate of creep resisting steels. Effect of acting stress components in particles disjunction matrix. Effect of ...increase of number of ferrite lattice vacancies.
In this paper, the influence of preferential grain orientation was examined. Parallel tests were conducted on the samples from the same steel strip, taken in the direction and perpendicular to the ...direction of rolling the strip. Steel strip has a homogeneous fine-grained ferrite-pearlite microstructure. Using the methods of thermography it has been found that at the beginning of the plastic flow Lüders bands occur, pointing to the fact that the preferential grain orientation, in the case of steel with the fine-grained ferrite-pearlite microstructure, has no effect on the appearance of the Lüders bands.
The primary creep of the parent metal (α), inter-critical (α+γ), and coarse-grained (γ) microstructures of simulated weld heat-affected zone (HAZ) for the steels X20CrMoV121 and X10CrMoVNb91, aged ...for 4 320 hours (6 months) at 750 °C and 17 520 hours (2 years) at 650 °C was analyzed. The time and creep strain at the transition point from primary to secondary creep were found to vary strongly between the parent metal and two simulated HAZ microstructures, especially after ageing at 750 °C.
Using thermal imaging camera during tensile testing of low carbon and Nb microalloyed steel influence of testing rate on start of plastic deformation was investigated. The results showed that the ...onset of plastic flow is significantly different in Nb steel. When testing Nb steel, above the yield point (Reh), Lüders bands formed and no change of temperature was recorded by increase of sample stretching force. Strain rate affects the propagation velocity of Lüders bands through the deformation zone.
One of the most influential microstructure constituents in creep resistant steels are carbide particles. Carbide particles act as obstacles to dislocations movement, therefore the creep rate strongly ...depends on their size and distribution. At elevated temperatures to which creep resistant steels are exposed, carbide morphology is altered by the coarsening mechanism, consequently deteriorating the creep resistance of these steels. The aim of this work is to study the role of size and distribution of carbide particles on creep rate. Different distributions and size of carbides were obtained by different heat treatment conditions. The effect of different carbide morphology on the creep resistance was evaluated by uniaxial constant load creep tests.
The article presents the results of measuring the amount of deformation during the formation and propagation of Lüders bands through the deformation zone. The amount of deformation was determined by ...applying the visioplasticity method with digital image correlation, and analyzing the captured images using the MatchID software package. Results show that during the formation of Lüders bands, the deformation of 0,004 mm/mm was achieved. Furthermore, it was determined that during the propagation of Lüders bands through deformation zone, the sample was deformed in the amount of 0,05 mm/mm.
