The performed investigations concerned the influence of the degree and temperature of deformation on the microstructure of metastable austenite in the stainless steel X5CrNi18-10 after its strain-induced martensitic transformation. Samples of steel strip were cold rolled within a degree of deformation from 20 % to 70 % and stretched at a low temperature of -196°C. The microstructure was observed by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM, HREM). It wasen found that after cold rolling with a small degree of deformation (20 %) in the tested steel, generally a single-phase microstructure of the matrix g is found with a high density of dislocations and numerous deformation bands morphologically characteristic of stainless steel with a low stacking-fault energy. After rolling with a 50 % thickness reduction, however, the microstructure displayed deformation twins as well as refined morphologic formations of the phase a', mostly localized in the vicinity of the grain boundaries of the metastable matrix g, and also trace amounts of carbide precipitates. In samples stretched at a temperature of -196°C the microstructure of the matrix displayed a considerable density of dislocations with lath areas of the martensite a' and precipitations of the carbides M23C6. Moreover, the tested steel revealed a crystallographic dependence of the planes and directions on the identified phases g and a', corresponding to dependences of the Kurdjumov-Sachs type, independent of the method and temperature of the plastic deformation. Tests carried out in the TEM proved that the typical sites of nucleation induced by the plastic deformation of martensite are the shear bands, particularly their intersection. The preferred mechanism of transformation, observed in the conditions of cold rolling is, however, a direct transformation of the type g (fcc) ® a' (bcc). Keywords: austenitic stainless steels, cold rolling, microstructure, phase transformation, strain-induced martensite Izvedene so bile preiskave vpliva temperature in stopnje deformacije na mikrostrukturo metastabilnega avstenita po njegovi pretvorbi v napetostno inducirani martenzit v jeklu X5CrNi18-10. Vzorci v obliki trakov so bili hladno valjani s stopnjo deformacije od 20 % do 70 % in natezani pri nizki temperaturi -196°C. Mikrostruktura je bila opazovana s pomo~jo vrsti~ne elektronske mikroskopije (SEM) in s presevno elektronsko mikroskopijo (TEM, HREM). Ugotovljeno je, da je po hladnem valjanju z majhno stopnjo deformacije (20 %) v preizku{anem jeklu dobljena enofazna mikrostruktura z osnovo g, z visoko gostoto dislokacij in {tevilnimi deformacijskimi pasovi, ki so morfolo{ka zna~ilnost nerjavnega jekla z nizko energijo napake zloga. Po valjanju s 50 % zmanj{anjem debeline, se v mikrostrukturi poka`ejo deformacijski dvoj~ki, kot tudi drobni nastanki faze a', ve~inoma v bli`ini mej zrn metastabilne osnove g in tudi sledi izlo~kov karbidov. V vzorcih natezno obremenjenih pri temperaturi -196°C je mikrostruktura osnove pokazala precej{njo ...
This paper presents the results of investigations on the effect of thermochemical treatment, boronising and chemical composition of selected structural steels on their wear in sliding friction process. The operation of boronising on C45, 37CrNiMo, 42CrMo6, 41Cr4, 50CrSi4-4 steels was performed by powder method at 950°C for 8 h. Following this operation, rod sections of the test steels were subjected to quench hardening from 850°C with isothermal holding at 300°C for 1h. The assessment of the construction, thickness and microhardness of boronised layers depending on the level of carbon and alloying elements in chemical composition of analysed steels was made. The testing for wear resistance of steels after boronising was carried out with the sliding friction method by applying a load of 150 N, counter-sample rotational speed of 1000 rpm and using aqueous solution of potassium chromate as a cooling medium. The metallographic observations of the structure and thickness measurement of the boronised layers were carried out using a light microscope, while the identification of phases was made by the X-ray qualitative analysis method. The hardness and microhardness measurements were taken by the Vickers method.
This paper presents the results of investigations that allow us to determine the influence of the temperature of plastic deformation in the range from 20°C to 800°C during static tensile tests on the mechanical properties and structure of low-alloy copper alloys of the type CuCo2 and CuCo2B, completed by measurements of the microhardness and observations of the structure in a light microscope, and also of fractures in a scanning electron microscope. Based on the results of these investigations the temperature range for the occurrence of the reduced plasticity of the alloys CuCo2 and CuCo2B could be determined. Keywords: low-alloy copper, plastic deformation, structure, mechanical properties, brittlenesŝ lanek predstavlja rezultate preiskav, ki omogo~ajo opredelitev vpliva temperature na plasti~no deformacijo v obmo~ju od 20°C do 800°C s stati~nimi nateznimi preizkusi na mehanske lastnosti in strukturo malo legiranih bakrovih zlitin, vrste CuCo2 in CuCo2B, izvedenih z merjenjem mikrotrdote ter opazovanjem mikrostrukture v svetlobnem mikroskopu in prelomov v vrsti~nem elektronskem mikroskopu. Na osnovi rezultatov teh preiskav je bilo mogo~e opredeliti temperaturno podro~je pojava zmanj{anja plasti~nosti zlitin vrste CuCo2 in CuCo2B. Klju~ne besede: malo legirani baker, plasti~na deformacija, struktura, mehanske lastnosti, krhkost
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.