Evolution of Oxide Particles during Fabrication Processes of 12Cr ODS Steel

2012 ◽  
Vol 1383 ◽  
Author(s):  
Xiaodong Mao ◽  
Tae Kyu Kim ◽  
Sung-Soo Kim ◽  
Chang Hee Han ◽  
Kyu Hwan Oh ◽  
...  
Keyword(s):  
Hot Rolling ◽  
Rolling Process ◽  
Face Centered Cubic ◽  
Metal Powders ◽  
Heat Treated Sample ◽  
Ods Steel ◽  
Treated Sample ◽  
The Matrix ◽  
Oxide Particles ◽  
Face Centered

ABSTRACT12Cr ODS steel samples were prepared by mechanical alloying of the metal powders with 20-30 nm Y2O3 particles followed by isostatic pressing, hot rolling and final heat treatment. Evolutions of oxide particles such as YTaO4 and YCrO3 after each fabrication step were investigated by using TEM with EDS. Crystallographic correlation between oxide particles and the matrix was investigated in a HIPped sample, and interactions between dislocations and oxide particles were observed in hot rolled or heat treated sample. Size distributions of oxide particles were measured by carbon replica samples and it was found that coarsening of oxide particles from 9 to 12 nm occurred during hot rolling process. Additional isothermal annealing at 1250 ˚C revealed that phase transformation of oxide particles from monoclinic YTaO4 to face centered cubic Y3TaO7 was observed.

scholarly journals Formation Mechanism of Voids around Hard Inclusion during Hot Rolling Processes

2018 ◽  
Vol 37 (8) ◽  
pp. 717-723
Author(s):  
Rong Cheng ◽  
Jiongming Zhang ◽  
Bo Wang
Keyword(s):  
Formation Mechanism ◽  
Hot Rolling ◽  
Rolling Process ◽  
Relative Displacement ◽  
Hard Inclusion ◽  
Hot Rolling Process ◽  
The Matrix ◽  
Soft Inclusion ◽  
Contact Surfaces ◽  
Plastic Slab

AbstractTo investigate the mechanism by which voids form around hard inclusions, the deformations of a plastic slab with hard and soft inclusions that form inside it during the hot rolling process have been simulated with a finite element method. By comparing plastic strain distributions, the relative displacements of contact surfaces, and the deformations between hard and soft inclusions have preceded analysis of the formation mechanism of these voids. The variations of strain measurements between the matrix and hard inclusions cause relative displacement of their contact surfaces. Therefore, voids occur at the front and rear of the hard inclusions. Trials on the slab deformations using a titanium ball instead of the soft inclusion inside the slab during the hot rolling process are conducted. The simulated shapes of the soft inclusions with different reductions mostly agree with the experimental results.

Microstructure and Mechanical Properties of the W-Ni-Co System Refractory High-Entropy Alloys

2015 ◽  
Vol 816 ◽  
pp. 324-329 ◽  
Author(s):  
Hui Jiang ◽  
Li Jiang ◽  
Yi Ping Lu ◽  
Tong Min Wang ◽  
Zhi Qiang Cao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vacuum Arc ◽  
High Entropy Alloys ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Melting Temperatures ◽  
Arc Melting ◽  
Microstructure And Mechanical Properties ◽  
The Matrix ◽  
Face Centered

The elements Mo, Cr and V were added to the W-Ni-Co system high entropy alloys, the effects of these added elements on microstructure and mechanical properties of these alloys were studied. The alloys were produced by vacuum arc melting. The compositions were W0.5Ni2Co2VMo0.5,W0.5Ni2Co2VCr0.5and W0.5Ni2Co2CrMo0.5(denoted as Alloy 1, Alloy 2 and Alloy 3) respectively. The theoretical melting temperatures were higher than 2000 K. X-ray diffraction, SEM and energy dispersive spectroscopy (EDS) results indicated that the matrix of the alloys is face-centered cubic (FCC) solid-solution, the alloys showed dendrite crystal structure. Ni, Co elements were enriched in the dendrite areas, the W, Mo were enriched in the inter-dendrite regions ,while V, Cr elements were uniform distribution. The Vickers hardness of these alloys was 376.1 HV, 255.88 HV and 306.8 HV, respectively. The yield strength values (σ0.2) of Alloy 1, Alloy 2 and Alloy 3 were approximately 1000MPa, 750MPa, 250MPa, respectively. The alloys show good compression plasticity deformation capacity at RT.

Analysis of Microstructures and XRD of a Gradient Boron Alloyed Composite Material

2013 ◽  
Vol 680 ◽  
pp. 113-118
Author(s):  
Guo Liang Xie ◽  
Qiang Song Wang ◽  
Xu Jun Mi ◽  
Bai Qing Xiong ◽  
Jing Tao Han ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Composite Material ◽  
Hot Rolling ◽  
Rolling Process ◽  
The Core ◽  
The Matrix ◽  
New Type ◽  
And Performance ◽  
Hot Rolled ◽  
Stainless Steel Coatings

A new type of gradient boron alloyed composite material, containing boron alloyed core layers and stainless steel coatings around the core, were designed and prepared by composite casting and hot rolling. The evolution of microstructures, phases and precipitations, as well as their influence on hot rolling process and performance are investigated. A mixture of austenitic matrix and uniformly distributed borides are obtained in the hot rolled stainless steel with 2-2.5 % boron, while massive borides are in the length of 80-120 μm together with micro gaps at the interface between the borides, and the matrix is remained after hot rolling for the core layers with higher boron contents. Hot deformation would be hindered since more precipitations of these orthorhombic or tetragonal phases occur with an increase of the boron concentration in the core layers.

scholarly journals Synthesis of Non-Cubic Nitride Phases of Va-Group Metals (V, Nb, and Ta) from Metal Powders in Stream of NH3 Gas under Concentrated Solar Radiation

2021 ◽  
Vol 5 (2) ◽  
pp. 19
Author(s):  
Nobumitsu Shohoji ◽  
Fernando Almeida Costa Oliveira ◽  
José Galindo ◽  
José Rodríguez ◽  
Inmaculada Cañadas ◽  
...  
Keyword(s):  
Lattice Structure ◽  
Solar Furnace ◽  
Degree Of Crystallinity ◽  
Nitride Phase ◽  
Face Centered Cubic ◽  
Metal Powders ◽  
Group Metal ◽  
Ε Phase ◽  
Δ Phase ◽  
Face Centered

Using a high-flux solar furnace, loosely compacted powders of Va-group transition metal (V, Nb, and Ta) were reacted with stream of NH3 gas (uncracked NH3 gas) being heated by concentrated solar beam to a temperature (T) range between 600 and 1000 °C. From V, sub-nitride V2N (γ phase) and hypo-stoichiometric mono-nitride VN possessing fcc (face-centered cubic) crystal lattice structure (δ phase) were synthesized. On the other hand, in the reaction product from Nb and Ta, hexagonal mono-nitride phase with N/M atom ratio close to 1 (ε phase) was detected. The reaction duration was normalized to be 60 min. In a conventional industrial or laboratory electric furnace, the synthesis of mono-nitride phase with high degree of crystallinity that yield sharp XRD peaks for Va-group metal might take a quite long duration even at T exceeding 1000 °C. In contrast, mono–nitride phase MN of Va-group metal was synthesized for a relatively short duration of 60 min at T lower than 1000 °C being co-existed with lower nitride phases.

Anti-Twinning in an Ni-Mo-Cr Alloy

2013 ◽  
Vol 203-204 ◽  
pp. 254-257
Author(s):  
Mirosław Wróbel ◽  
Elżbieta Stępniowska ◽  
Stanisław Dymek
Keyword(s):  
Long Range ◽  
The Body ◽  
Type I ◽  
Face Centered Cubic ◽  
The Matrix ◽  
The Face ◽  
Face Centered ◽  
Long Range Ordering ◽  
Mechanical Twins ◽  
Crystallographic Orientations

Two morphological types of mechanical twins occur in the microstructure of cold rolled Ni-Mo-Cr alloy: long – passing over whole grains and micro-twins – confined to individual long range ordered domains. Long mechanical twins were only formed in the disordered alloy. Such twins are typical for metals with the face centered cubic structure with relatively low stacking fault energy. They do not form in the grains with twinning prohibited crystallographic orientations, e.g. {110}. Both types of twins were found in an alloy subjected to prolong annealing at 650 °C. The annealing induces long range ordering reaction leading to the formation of ordered domains with the body centered orthorombic crystal structure (oI8). The twins were of type I, type II, compound twins or pseudo-twins, depending on the crystallographic orientation of the ordered phase in relation to the matrix. It was found that twins of such types were formed even in grains with the {110} orientation and result from the anti-twinning deformation. However, in this orientation they were confined to ordered domains rather than developed into the long form crossing entire grains. On the other hand, the long twins of various types were formed in grains with other twinning favoring crystallographic orientations.

scholarly journals Co-introduction of precipitate hardening and TRIP in a TWIP high-entropy alloy using friction stir alloying

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tianhao Wang ◽  
Shivakant Shukla ◽  
Bharat Gwalani ◽  
Subhasis Sinha ◽  
Saket Thapliyal ◽  
...  
Keyword(s):  
Current Approach ◽  
Deformation Mechanisms ◽  
Engineering Properties ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Friction Stir ◽  
The Matrix ◽  
Face Centered ◽  
Multiple Deformation

AbstractTuning deformation mechanisms is imperative to overcome the well-known strength-ductility paradigm. Twinning-induced plasticity (TWIP), transformation-induced plasticity (TRIP) and precipitate hardening have been investigated separately and have been altered to achieve exceptional strength or ductility in several alloy systems. In this study, we use a novel solid-state alloying method—friction stir alloying (FSA)—to tune the microstructure, and a composition of a TWIP high-entropy alloy by adding Ti, and thus activating site-specific deformation mechanisms that occur concomitantly in a single alloy. During the FSA process, grains of the as-cast face-centered cubic matrix were refined by high-temperature severe plastic deformation and, subsequently, a new alloy composition was obtained by dissolving Ti into the matrix. After annealing the FSA specimen at 900 °C, hard Ni–Ti rich precipitates formed to strengthen the alloy. An additional result was a Ni-depleted region in the vicinity of newly-formed precipitates. The reduction in Ni locally reduced the stacking fault energy, thus inducing TRIP-based deformation while the remaining matrix still deformed as a result of TWIP. Our current approach presents a novel microstructural architecture to design alloys, an approach that combines and optimizes local compositions such that multiple deformation mechanisms can be activated to enhance engineering properties.

scholarly journals Effects of Intermetallic Microstructure on Degradation of Mg-5Nd Alloy

2020 ◽  
Vol 51 (10) ◽  
pp. 5498-5515 ◽  
Author(s):  
Yaping Zhang ◽  
Yuanding Huang ◽  
Frank Feyerabend ◽  
Sarkis Gavras ◽  
Yuling Xu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Grain Boundaries ◽  
Culture Conditions ◽  
Product Layer ◽  
Heat Treated Sample ◽  
Corrosion Propagation ◽  
Heat Treated ◽  
Treated Sample ◽  
The Matrix ◽  
Immersion Testing

Abstract The influence of intermetallic microstructure on the degradation of Mg-5Nd alloy with different heat treatments was investigated via immersion testing in DMEM + 10 pct FBS under cell culture conditions and subsequent microstructural characterizations. It was found that T4 heat-treated sample had the poorest corrosion resistance due to the lack of finely dispersed precipitates inside grains, continuous lamellar particles along grain boundaries and outer Ca-P layer, and to the formation of a loose corrosion product layer. In contrast, the aged samples exhibited a better corrosion resistance due to their presence and to the formation of a compact corrosion layer. Their degradation behavior largely depended on the intermetallic microstructure. Corrosion was initiated in the matrix around stable globular particles Mg41Nd5 at grain boundaries. In the sample aged at high temperature 245 °C, the coexistence of lamellar Mg41Nd5 particles and their nearby Nd-poor regions enhanced the corrosion. The corrosion first started in such regions. It was shown that those finely dispersed precipitates formed during aging had no influence on the corrosion initiation. However, they indeed affected the subsequent corrosion propagation with the immersion proceeding. They supplied barriers for corrosion propagation and hence were beneficial for improving the corrosion resistance. The continuously distributed lamellar Mg41Nd5 precipitates formed at grain boundaries during aging at 245 °C supplied an additional effective obstacle to corrosion propagation. This was especially beneficial for hindering the corrosion propagation at the later stage of corrosion.

Formation of Ti-Matrix Composites for Lightweight Structural Components by Mechanical Alloying and Subsequent Annealing

2006 ◽  
Vol 514-516 ◽  
pp. 609-613 ◽  
Author(s):  
Bruno Trindade ◽  
Marco Caetano ◽  
Nelson Duarte
Keyword(s):  
Solid Solution ◽  
Mechanical Alloying ◽  
Matrix Composites ◽  
Structural Components ◽  
Mechanically Alloyed ◽  
Heat Treated Sample ◽  
Heat Treated ◽  
Treated Sample ◽  
The Matrix ◽  
Matrix Hardness

In this work, a lightweight Ti-10Mg-5Al (wt. %) alloy for structural components was produced by mechanical alloying. A metastable α-Ti(Al,Mg) solid solution was obtained after 50h of milling. Diffraction peaks ascribed to the Mg phase were detected in the XRD pattern of the sample heat treated at 600°C. This phase tends to oxidize with the increase of temperature giving rise to MgO. The structure of the mechanically alloyed and 900°C heat treated sample consisted of a Ti(Al) solid solution with dispersed MgO particles in the matrix. Hardness and Young’s modulus values obtained from ultramicrohardness tests confirm the strength improvement of the Ti-based alloy due to the MgO reinforcement.

scholarly journals Relationship between Microstructure and Properties of Cu–Cr–Ag Alloy

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 732
Author(s):  
Dong Liang ◽  
Xujun Mi ◽  
Lijun Peng ◽  
Haofeng Xie ◽  
Guojie Huang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Cold Deformation ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Face Centered Cubic ◽  
Transmission Electron ◽  
The Matrix ◽  
Bcc Structure ◽  
Continuous Extrusion ◽  
Face Centered

The microstructure evolution and properties of a Cu–Cr–Ag alloy during continuous extrusion and an aging process were studied by Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). Owing to strong shear deformation that happened during continuous extrusion with working temperatures of 450 to 480 °C, a larger number of fine grains were obtained. Both face-centered cubic (FCC) and body-centered cubic (BCC) precipitates simultaneously existed in the matrix when aged for 450 °C for 2 h, and the Cr phases with BCC structure had an N–W relationship with the matrix. After continuous extrusion, 60% cold deformation, 875 °C × 1 h solid solution treatment, 60% cold deformation, 450 °C × 2 h aging treatment, and 70% cold deformation, the Cu–Cr–Ag alloy acquired excellent comprehensive properties: tensile strength of 494.4 MPa, yield strength of 487.6 MPa, and electrical conductivity of 91.4% IACS.

scholarly journals Effects of C Addition on the Microstructures of As-Cast Cu–Fe–P Alloys

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2772 ◽  
Author(s):  
Chen ◽  
Hu ◽  
Guo ◽  
Zou ◽  
Liu ◽  
...  
Keyword(s):  
Orientation Relationship ◽  
Supersaturated Solid Solution ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Matrix Microstructure ◽  
The Matrix ◽  
Bcc Structure ◽  
The Difference ◽  
Face Centered ◽  
Fcc Structure

Effects of C addition on the microstructures of as-cast Cu–Fe–P (mass fraction) alloys were systematically investigated. The results show that C addition can refine the matrix microstructure and make Fe particles finer. The Fe particles observed in both the non-C-alloyed and C-alloyed specimens are α-Fe particles, which possess a body-centered cubic (bcc) structure with a Nishiyama–Wassermann orientation relationship with the matrix. C is reported to be an γ-Fe stabilizer in the literature. The reason for the difference between the phases of Fe particles observed in this study, and that reported in the literature, are finally discussed. Additionally, C addition facilitates the decomposition of the supersaturated solid solution which occurs by the simultaneous precipitation of very fine Fe particles. Such initial decomposition product has an face-centered cubic (fcc) structure with a cube-on-cube orientation relationship with the matrix.

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