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| 2. |
- Dudrova, E, et al.
(author)
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Improvement of Strength Properties of Fe-Cr-Mo-[Cu-Ni]-C Sintered Steels by Sinter-Hardening
- 2010
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In: World Powder Metallurgy Congress and Exhibition, World PM 2010; Florence; Italy; 10 October 2010 through 14 October 2010. - 9781899072194 ; 3, s. 79-86
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Conference paper (peer-reviewed)abstract
- The effect of high temperature sintering and high cooling rate on shifting the microstructure composition to favourably portion of high strength structures and thus strength properties improvement of the Fe-Cr-Mo-[Cu-Ni]-C sintered steels based on Astaloy CrL was investigated. All the systems were processed by both sinter-hardening and conventional sintering. The high temperature vacuum sintering (11800C) was integrated with high (6K/s), medium (3K/s) and slow (0.1K/s) cooling rates; the conventional sintering at 11800C with the cooling rate of ~0.17K/s was carried out in N2-rich atmosphere. Depending on chemical composition, the yield and tensile strengths of 890-1150 MPa and 913 -1230 MPa were achieved by the applied sinter-hardening. All the values are approximately double than those for pearlite/bainite structures after conventional sintering. Finally, basing on the microstructure composition and corresponding microhardness, the (theoretical) tensile strength of the “pore free” matrix was calculated. The difference between calculated and experimental tensile strength values was explained by microfractographic observations.
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| 3. |
- Dudrova, Eva, et al.
(author)
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MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Fe-Cr-Mo-[Cu-Ni]-C SINTERED STEELS
- 2010
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In: Acta Metallurgica Slovaca - Conference. - 1338-1660. ; 1, s. 580-585
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Journal article (peer-reviewed)abstract
- The effect of high-temperature vacuum sintering (11800C) integrated with high (6K/s), medium (3K/s) and slow (0.1K/s) cooling rates and conventional sintering at 11800C with cooling rate of ~0.17K/s on shifting the microstructural composition to significant portion of martensite-bainite and thus effective improvement of mechanical properties of Fe-Cr-Mo-[Cu-Ni]-C sintered steels (Astaloy Cr+1 and 2% Cu and/or 50% Distaloy AB powder was investigated. In dependence on chemical composition the yield and tensile strengths of 890-1150 MPa and 913-1230 MPa and impact energy of 10-15 J were achieved by sinter-hardening. The yield and tensile strengths were approximately double than those resulting from conventional sintering.
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| 4. |
- Dudrova, Eva, et al.
(author)
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Improvement of Mechanical Properties of Fe-Cr-Mo-[Cu-Ni]-C Sintered Sintered Steels by Sinter Hardening
- 2011
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In: Materials Science Forum. - 1662-9752 .- 0255-5476. ; 672, s. 31-38
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Journal article (peer-reviewed)abstract
- The effect of high temperature sintering and high cooling rate on shifting themicrostructural composition to the favourably of martensite-bainite structures and thus effectiveimprovement of mechanical properties of sintered steels based on Astaloy CrL powder with anaddition of 1 and 2% Cu or 50% Distaloy AB powder and 0.65% C was investigated. All thesystems were processed by both sinter-hardening and conventional sintering. The vacuum sinteringat high-temperature of 1240 0C and at common temperature of 1180 0C were integrated with high(6 0C/s), medium (3 0C/s) and slow (0.1 0C/s) cooling rates; conventional sintering at 1180 0C withcooling rate of ~0.17 0C/s was carried out in a N2+10%H2 atmosphere. In dependence on chemicalcomposition, the yield and tensile strengths of 890-1150 MPa and 913-1230 MPa respectively andimpact energy of 10-15 J were achieved by sinter-hardening. The yield and tensile strengths areapproximately double than those resulting from conventional sintering.
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| 5. |
- Alexanderson, H, et al.
(author)
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Patient-reported outcomes and adult patients' disease experience in the idiopathic inflammatory myopathies. report from the OMERACT 11 Myositis Special Interest Group
- 2014
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In: The Journal of rheumatology. - : The Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 41:3, s. 581-592
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Journal article (peer-reviewed)abstract
- The newly formed Outcome Measures in Rheumatology (OMERACT) Myositis Special Interest Group (SIG) was established to examine patient-reported outcome measures (PROM) in myositis. At OMERACT 11, a literature review of PROM used in the idiopathic inflammatory myopathies (IIM) and other neuromuscular conditions was presented. The group examined in more detail 2 PROM more extensively evaluated in patients with IIM, the Myositis Activities Profile, and the McMaster-Toronto Arthritis Patient Preference Disability Questionnaire, through the OMERACT filter of truth, discrimination, and feasibility. Preliminary results from a qualitative study of patients with myositis regarding their symptoms were discussed that emphasized the range of symptoms experienced: pain, physical tightness/stiffness, fatigue, disease effect on emotional life and relationships, and treatment-related side effects. Following discussion of these results and following additional discussions since OMERACT 11, a research agenda was developed. The next step in evaluating PROM in IIM will require additional focus groups with a spectrum of patients with different myositis disease phenotypes and manifestations across a range of disease activity, and from multiple international settings. The group will initially focus on dermatomyositis and polymyositis in adults. Qualitative analysis will facilitate the identification of commonalities and divergent patient-relevant aspects of disease, insights that are critical given the heterogeneous manifestations of these diseases. Based on these qualitative studies, existing myositis PROM can be examined to more thoroughly assess content validity, and will be important to identify gaps in domain measurement that will be required to develop a preliminary core set of patient-relevant domains for IIM.
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| 6. |
- Andersson, A. K. E., et al.
(author)
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Chemical Expansion Due to Hydration of Proton-Conducting Perovskite Oxide Ceramics
- 2014
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In: Journal of the American Ceramic Society. - : Wiley. - 0002-7820 .- 1551-2916. ; 97:8, s. 2654-2661
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Journal article (peer-reviewed)abstract
- The crystal structures of proton-conducting BaZr1-xYxO3-x/2 (BZY05-BZY20) and BaCe0.8Y0.2O2.9 (BCY20) during hydration/dehydration has been studied by in situ high-temperature X-ray diffraction and thermal analysis. A contraction/expansion of the crystal lattice associated with dehydration/hydration was observed for all materials at elevated temperatures and the polymorphic phase transition temperatures of BaCe0.8Y0.2O2.9 were depressed by lowering the vapor pressure of water. A thermodynamic formalism is introduced to describe the chemical expansion associated with the hydration of oxygen vacancies in acceptor-doped oxides. A conventional point defect model was applied to describe the lattice strain associated with the hydration. The chemical expansion is discussed with respect to the available volumetric data on the hydration of proton-conducting oxide materials and its likely impact on ceramic fuel cells/hydrogen separation membranes utilizing a proton-conducting electrolyte.
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| 7. |
- Bidulsky, Robert, et al.
(author)
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The Effect of Manganese on Microstructure Development and Diffusion Characteristics in Admixed Fe-Mn-C Sintered Steels
- 2010
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In: World Powder Metallurgy Congress and Exhibition, World PM 2010; Florence; Italy; 10 October 2010 through 14 October 2010. - 9781899072125 ; 3, s. 113-120
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Conference paper (peer-reviewed)abstract
- The aim of this work is to determine the effect of manganese on the microstructure development of admixed Fe-Mn-C sintered steels, as well as to study the diffusion characteristics of Mn in the Fe matrix. Admixed systems were prepared on the base of sponge iron powder, with addition of 0.3 % C and 3% Mn added as ferromanganese. Sintering was carried out in laboratory tube furnace in an atmosphere of pure gases mixture 25 % N2 + 75 % H2 with the dew point of -30°C. The specimens were sintered at 750, 900, 1050, 1150 and 1200°C for 3 minutes. The obtained microstructures were complex and graded due to the local chemical heterogeneities of these materials with different Mn and C concentration. More detailed investigation reveal that diffusion induced grain boundary migration (DIGM) is the dominant alloying mechanism in sintered manganese steels. On the basis of presented results, Mn apparent diffusion coefficient and penetration depth were calculated.
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