Browsing by Subject "annealing"

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Access status: Open Access ,
Annealing effect on microstructure and chemical composition of Inconel 625 alloy
(Wydawnictwa AGH, 2018) Petrzak, Paweł; Kowalski, Kazimierz; Rozmus-Górnikowska, Magdalena Monika; Dębowska, Aleksandra; Jędrusik, Mateusz; Koclęga, Damian
Our research focused on Inconel 625 weld overlays on 16Mo3 steel boiler pipes. The investigation focused on the characterization of changes in the microstructure and chemical composition after annealing. The annealing was performed for ten hours at temperatures from 600 to 1000°C. Changes in the microstructure were observed with a scanning and transmission electron microscope (SEM and TEM). The investigation was supplemented by hardness measurements.
Access status: Open Access ,
Influence of annealing conditions on the properties and microstructure of steel composites
(2014) Sulima, Iwona; Hyjek, Paweł; Tokarski, Tomasz
Samples made of AISI 316L stainless steel reinforced with 8 vol.% TiB2 particles were prepared using the high pressure-high temperature (HP-HT) method. Next, the composites were annealed at a temperature of 1200°C for different holding times. The influence of the annealing temperature and time on the properties and microstructure of AISI316L+8% vol.TiB2 composites was investigated. The structural studies showed the formation of phases containing chromium, molybdenum and boron.
Access status: Open Access ,
Mechanical properties and structure evolution of the AZ91 magnesium alloy after hot rolling and annealing
(2015) Sułkowski, Bartosz; Boczkal, Grzegorz
The AZ91 magnesium alloy was processed up to 87.5% of total thickness reduction in several thermodynamic routes, consisted of hot rolling and intermediate annealing. The hot-rolling process was performed at a high strain rate equal to 1.6 s−1 and at a temperature of 430°C. The intermediate annealing was performed at 430°C for 15 minutes after each route. It was found that, during hot rolling, the hardness of the material increased from 32 HV to 40 HV, and the structure investigations showed a huge amount of twins formed inside the grains (which were not observed after annealing). Tensile tests have shown strong anisotropy in mechanical properties of the “as-rolled” samples dependent onthe orientation between tension direction (TD) and rolling direction (RD). The samples with TD perpendicular to RD provedhigher ultimate tensile strength (UTS) and (on the other hand) worse plastic properties as compared to the samples with TD parallel to RD. The annealing has an effect on the reduction of mechanical properties anisotropy. X-ray investigations have shown texture changes from the basal type with the additional (0001) <1120> component for “as-rolled” samples to the texture with the main (0001) <1010> component for annealed samples. The texture changes had a great impact on the anisotropy of mechanical properties of the investigated AZ91 magnesium alloy.
Access status: Open Access ,
Structure and properties of hot-rolled and annealed AZ61 magnesium alloy
(2017) Sułkowski, Bartosz
Magnesium alloy AZ61 was processed by hot rolling up to a large thickness reduction (~89%) in several routes with intermediate annealing. The hot rolling process was conducted at 450°C and at a 1.5 s−1 strain rate. The structure and texture evolution as well as the mechanical properties during processing were investigated. The structure studies showed that, during the hot-rolling process, a large number of twins formed, which had an impact on the mechanical properties of the hot-rolled samples. After annealing for 15 minutes, the twins were no longer observed in the annealed samples, causing a significant decrease in hardness. Moreover, an investigation of the hardness showed that annealing for 15 minutes did not remove all of the hardening effects nor did the hardness of the annealed samples decrease to the value before hot rolling. The texture investigations showed that the texture of the hot-rolled samples was a typical basal-type texture. However, the basal pick was split into two tilted towards the rolling direction (RD). The texture changed during annealing while the new strong texture components evolved. The annealing led to an increased intensity of <1010>{1120} texture component and enhanced ductility. It was concluded that the texture changes observed in the present investigations may lead to the enhanced ductility of magnesium alloys and, therefore, help us design a deformation scheme for magnesium alloys consisting of several thermomechanical routes.
Access status: Open Access ,
Technological research of calcinated dolomite ores as intermediates for metal magnesium production
(Wydawnictwa AGH, 2025) Bekényiová, Alexandra; Danková, Zuzana; Kollová, Zuzana; Fedorová, Erika; Bačo, Pavel; Briančin, Jaroslav; Čechovská, Katrína
The current work investigates the differences between four types of calcinated dolomite samples as suitable intermediates for subsequent silicothermic reduction of metal magnesium by simultaneous differential thermal analysis (DTA) /thermogravimetric analysis (TG). The results of the DTA/TG analysis showed the least significant differences at the temperature endotherms with no weight loss on the TG curves at a temperature of 1373 K for the calcined dolomite sample TR-1 from Trebejov deposit. The most significant difference on the DTA curves was detected for the calcinated sample KRA-1 (deposit Kraľovany), which is connected with the hydration activity of the sample. According to the results of the chemical analyses, annealing products of all samples fulfilled two of the three conditions, namely a molecular ratio of CaO:MgO and an impurity content below 2.5% for their subsequent use as feedstocks in the silicothermal process for the preparation of metallic magnesium. Subsequently, the experimental test of silicothermic reduction of magnesium of calcinated sample ST-1 in a flowing argon atmosphere was investigated by EDX analysis. The results indicate that the prepared magnesium sample analysed by EDX – point and mapping analysis confirmed the presence of magnesium totalling 91% despite the failure to reach the temperature in the furnace required for the reduction of Mg.