Reduced argon bubble formation in oxide dispersion strengthened steels by high-energy mechanical alloying

2016 ◽  
Vol 113 ◽  
pp. 31-34
Author(s):  
Eun-Kwang Park ◽  
Sung-Mo Hong ◽  
Gyoung-Ja Lee ◽  
Jin-Ju Park ◽  
Min-Ku Lee ◽  
...  
2020 ◽  
Vol 21 (1) ◽  
pp. 35
Author(s):  
Marzuki Silalahi ◽  
Bernadus Bandriyana ◽  
Arbi Dimyati ◽  
Bambang Sugeng ◽  
Syahfandi Ahda ◽  
...  

Microstructure and phase distribution of innovative Oxide Dispersion Strengthened (ODS) steel based on Fe-Cr-ZrO2 particularly for application at high temperature reactor with variation of Cr content was analysed. The alloy was synthesized with Cr composition variation of  15, 20 and 25 wt.% Cr, while zirconia dispersoid kept constant at 0.50 wt.%. The samples was synthesized by mechanical alloying comprising of high energy milling for 3 hours followed by vibrated compression with iso-static load at 20 ton. The final consolidation was performed via sintering process for 4 minutes using the Arc Plasma Sintering (APS) technique, a new method developed in BATAN especially for synthesizing high temperature materials. The samples were then characterized by means of scanning electron microscopy (SEM) with energy dispersed X-ray (EDX) analysis capability and X-ray diffraction. The mechanical property of hardness was measured using standard Vickers micro hardness tester to confirmed the microstructure analysis.  The results show that the microstructure of the ODS alloy samples in all variation of Cr content consists generally of cubic Fe-Cr matrix phase with small of porosity and  Zirconia particles distributed homogenously in and around the matrix grains. The achievable hardness was between 142 and 184 HVN dependent consistently on Cr content in which Cr element may cause grain refining that in turn increase the hardness.


2018 ◽  
Vol 941 ◽  
pp. 257-262
Author(s):  
Massimo de Sanctis ◽  
Alessandra Fava ◽  
Gianfranco Lovicu ◽  
Roberto Montanari ◽  
Maria Richetta ◽  
...  

An oxide dispersion strengthened (ODS) ferritic steel with nanometric grain size has been produced by means of low-energy mechanical alloying (LEMA) of steel powder (Fe-14Cr-1W-0.4Ti) mixed with Y2O3 particles (0.3 wt%) and successive hot extrusion (HE). The material has equiaxed grains (mean size of 400 nm) and dislocation density of 4 x 1012 m-2, and exhibits superior mechanical properties with respect the unreinforced steel. The mechanical behavior has been compared with that of ODS steels prepared by means of the most common process, high-energy mechanical alloying (HEMA), consolidation through hot isostatic pressing (HIP) or hot extrusion (HE), annealing around 1100 °C for 1-2 hours, which produces a bimodal grain size distribution. The strengthening mechanisms have been examined and discussed to explain the different behavior.


1996 ◽  
Vol 460 ◽  
Author(s):  
B. J. Inkson ◽  
P. L. Threadgill

ABSTRACTThe microstructure of an oxide dispersion strengthened FeAl (Zr,B) alloy, manufactured by mechanical alloying then extrusion, has been examined by HREM. Y2O3 is dispersed throughout the FeAl matrix as particles, ranging in size from 5nm upwards, which are effective in pinning the bulk dislocations. Although in the main the observed oxide particles are irregular in morphology, a significant minority of particles exhibit faceted surfaces. In particular, the facets of the Y2O3 particles are observed to coincide with {100}B2, {110}B2 and {112}B2 planes of the surrounding bulk FeAl matrix. In addition, HREM imaging reveals uncoupled 1/2<111>FeAl superpartial dislocations lying a few nanometres from some of the FeAl - Y2O3 interfaces.


2010 ◽  
Vol 1264 ◽  
Author(s):  
Olena Kalokhtina ◽  
Bertrand Radiguet ◽  
Yann de Carlan ◽  
Philippe Pareige

AbstractA high chromium ferritic Oxide Dispersion Strengthened steel was produced by mechanical alloying of Fe-18Cr-1W-0.3Ti-0.3Ni-0.15Si and 0.5% Y2O3 (wt.%) powders in industrial attritor, followed by hot extrusion at 1100°C. The material was characterized by Atom Probe Tomography on each step of manufacturing process: as-milled powder and in final hot extruded state. In addition, to get information on clustering kinetics the powder was also characterized after annealing at 850°C during 1 hour. Atom Probe Tomography revealed that the oxide dispersion strengthened steel Fe-18Cr contains nanometer scale yttrium- and oxygen-enriched nanoclusters in as-milled state. Their evolution is shown after subsequent annealing and hot extrusion. More well defined nanophases also enriched in Ti are observed. A mechanism of their formation is proposed. Mechanical alloying results in supersaturated solid solution with presence of small Y- and O-enriched clusters. Subsequent annealing stimulates incorporation of Ti to the nucleii that were previously formed during mechanical alloying.


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