scholarly journals The Influence of Texture on the Ductile-to-Brittle Transition Behavior in Fe20Cr4.5Al Oxide Dispersion Strengthened Alloy

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 87
Author(s):  
Jesus Chao ◽  
Carlos Capdevila
Keyword(s):  
Yield Strength ◽  
Cleavage Plane ◽  
Phase Particle ◽  
Oxide Dispersion Strengthened ◽  
Dislocation Cell ◽  
The Other ◽  
Second Phase ◽  
Oxide Dispersion ◽  
Brittle Transition ◽  
Ductile To Brittle Transition

This paper reports on hardness, tensile properties and notch impact bending toughness values of an Fe20Cr4.5Al oxide dispersion strengthened (ODS) alloy specifically processed to achieved different preferential orientations: random, <100>, <110> and <111> parallel to the bar axis. In spite of the differences in the grain size, it was found for <100>, <111> and random orientations that the mean hardness values on the transverse cross sections is not remarkably sensitive to the texture. On the other hand, a significantly different mean hardness value for the material having the <110> crystalline orientation was found. Regarding the yield strength, it was found for random, <100> and <111> orientations that the yield strength is proportional to the Taylor’s factor. The difference between experimental and predicted yield strength values for <110> orientation was attributed to the offset effect induced by the dislocation cell size. The variation of the cleavage fracture strength with the texture was analyzed in the basis of two criteria: one based on the Normal Stress Law (macroscopic nature), and the other based on the assumption that fracture occurs from the propagation of a microcrack-like defect (microscopic nature). In this sense, it was concluded from the fractographic evidences that random and <100> orientations follow a mechanism where the fracture kinks along of the cleavage plane from a penny shaped microcrack nucleated in a second phase particle, meanwhile in the <110> and <111> orientations the fracture propagation arises from a penny shaped defect on the cleavage plane. Finally, the lower shelf values determined for the conditions studied are the same regardless of the texture and microstructure. The effect of texture on the notch toughness was noted where plastic flow predominates, i.e., in the ductile to brittle transition temperature and in the upper shelf energy.

scholarly journals Comparison of Ductile-to-Brittle Transition Behavior in Two Similar Ferritic Oxide Dispersion Strengthened Alloys

Materials ◽  
2016 ◽  
Vol 9 (8) ◽  
pp. 637 ◽  
Author(s):  
Jesus Chao ◽  
Rosalia Rementeria ◽  
Maria Aranda ◽  
Carlos Capdevila ◽  
Jose Gonzalez-Carrasco
Keyword(s):  
Oxide Dispersion Strengthened ◽  
Oxide Dispersion ◽  
Brittle Transition ◽  
Transition Behavior ◽  
Ductile To Brittle Transition

scholarly journals ODS EUROFER Steel Strengthened by Y-(Ce, Hf, La, Sc, and Zr) Complex Oxides

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1148 ◽  
Author(s):  
Roman Husák ◽  
Hynek Hadraba ◽  
Zdeněk Chlup ◽  
Milan Heczko ◽  
Tomáš Kruml ◽  
...  
Keyword(s):  
Grain Size ◽  
Yield Strength ◽  
Complex Oxides ◽  
Oxide Dispersion Strengthened ◽  
Interparticle Spacing ◽  
Oxide Dispersion ◽  
Strengthening Effect ◽  
Dispersion Strengthening ◽  
Doping Element ◽  
Average Grain Size

Oxide dispersion-strengthened (ODS) materials contain homogeneous dispersions of temperature-stable nano-oxides serving as obstacles for dislocations and further pinning of grain boundaries. The strategy for dispersion strengthening based on complex oxides (Y-Hf, -Zr, -Ce, -La) was developed in order to refine oxide dispersion to enhance the dispersion strengthening effect. In this work, the strengthening of EUROFER steel by complex oxides based on Y and elements of the IIIB group (lanthanum, scandium) and IVB group (cerium, hafnium, zirconium) was explored. Interparticle spacing as a dispersoid characteristic appeared to be an important factor in controlling the dispersion strengthening contribution to the yield strength of ODS EUROFER steels. The dispersoid size and average grain size of ODS EUROFER steel were altered in the ranges of 5–13 nm and 0.6–1.7 µm, respectively. Using this strategy, the yield strength of the prepared alloys varied between 550 MPa and 950 MPa depending on the doping element.

scholarly journals Experimental Investigation of EU-DEMO Breeding Blanket First Wall Mock-Ups in Support of the Manufacturing and Material Development Programmes

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7580
Author(s):  
Bradut-Eugen Ghidersa ◽  
Ali Abou Sena ◽  
Michael Rieth ◽  
Thomas Emmerich ◽  
Martin Lux ◽  
...  
Keyword(s):  
Infrared Camera ◽  
Oxide Dispersion Strengthened ◽  
Functionally Graded ◽  
The Other ◽  
Oxide Dispersion ◽  
First Wall ◽  
Material Development ◽  
Ods Steel ◽  
Steel Layer ◽  
Functionally Graded Layer

This paper presents the testing campaign of the two First Wall mock-ups in the HELOKA facility, one mock-up having a 3 mm thick Oxide Dispersion Strengthened (ODS) steel layer on its surface and the other featuring a tungsten functionally graded cover. Special consideration is given to the diagnostics used for these tests, in particular, the measurement of the surface temperature of the tungsten functionally graded layer with an infrared camera. Additionally, the paper looks into the uncertainty associated with the calorimetric evaluation of the applied heating power for these experiments.

scholarly journals Effects of initial microstructure on the earring of aluminium alloys cartridge case

10.30544/409 ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 11-22
Author(s):  
Ljubica M. Radovic ◽  
Jelena Marinkovic ◽  
Milorad Stanic
Keyword(s):  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Particle Distribution ◽  
Phase Particle ◽  
The Other ◽  
Second Phase ◽  
Local Difference ◽  
Cartridge Case ◽  
The One ◽  
Cartridge Cases

Defects obtained during impact extrusion of EN AW-5754 aluminium alloy during cartridge case production were investigated. In cartridge cases produced from the one metallurgical heat pronounced tendency to earing after impact extrusion observed/appeared. On the other hand the earing in cartridge cases from the other heat was not observed. Presence of earing is due to local difference in materials flow during extrusion. This behaviour is atriduted to dfference in second phase particle distribution in used preforms (slugs).

scholarly journals Microstructure Evolution and Mechanical Properties of As-Cast and As-Compressed ZM6 Magnesium Alloys during the Two-Stage Aging Treatment Process

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7760
Author(s):  
Jia Fu ◽  
Su Chen
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Grain Boundary ◽  
Aging Process ◽  
Treatment Process ◽  
Phase Particle ◽  
Aging Treatment ◽  
Grain Boundary Sliding ◽  
Second Phase ◽  
Two Stage

In the present study, different solid solution and aging processes of as-cast and as-compressed ZM6 (Mg2.6Nd0.4Zn0.4Zr) alloy were designed, and the microstructure and precipitation strengthening mechanisms were discussed. After the pre-aging treatment, a large amount of G.P. zones formed in the α-Mg matrix over the course of the subsequent secondary G.P. prescription, where the fine and dispersed Mg12(Nd,Zn) phases were precipitated at the grain boundaries. The pre-aging and secondary aging processes resulted in the Mg12(Nd, Zn) phase becoming globular, preventing grain boundary sliding and decreasing grain boundary diffusion. Meanwhile, precipitation phase â″(Mg3Nd) demonstrated a coherent relationship with the α-Mg matrix after the pre-aging process, and after the secondary aging phase, Mg12Nd increases and became semi-coherent in the matrix. Compared to an as-cast ZM6 alloy, the yield strength of the as-compressed ZM6 alloy increased sharply due to an increase in the yield strength that was proportional to the particle spacing, where the dislocation bypassed the second phase particle. Compared to the single-stage aging process, the two-stage aging process greatly improved the mechanical properties of both the as-cast and as-compressed ZM6 alloys. The difference between the as-cast and as-compressed states is that an as-compressed ZM6 alloy with more dislocations and twins has more dispersed precipitates in the G.P. zones after secondary aging, meaning that it is greatly strengthened after the two-stage aging treatment process.

Effect of the HTP to X80 Ferrite Steel Structure and Mechanical Properties

2011 ◽  
Vol 189-193 ◽  
pp. 4216-4220
Author(s):  
Yong Jie Ma ◽  
Guang Liang Zhang
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Pipeline Steel ◽  
Steel Structure ◽  
The Other ◽  
Good Effect ◽  
Brittle Transition ◽  
Fine Microstructure ◽  
Ferrite Steel ◽  
Brittle Transition Temperature

The structure and mechanical properties of pipeline steel X80 through HTP rolled into 16mm thick slab were tested. The results show that the yield strength of tested has reached above 600Mpa, and the ratio of tensile strength to yield strength is 0.86, and duetile brittle transition temperature is lower than -60°C , and good strength and toughness are obtained. Low content of P, S, high content of Mn and fine microstructure have good effect on reducing the ductile-brittle transitiop temperature. Two different precipitations are observed in pipeline steel X80, a class of TiN precipitations is mainly and a small number of (Nb, V)(C, N) complex precipitations in the TiN around, and the other for large number of NbC precipitations and a small amount of TiC、VC and simultaneous deposition of the complex formed precipitations. Remarkable strengthening and grain refinement can ne caused by these precipitations.

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