Effect of Microstructure on Impact Energy of an Al-Mg-Sc Alloy

2016 ◽  
Vol 877 ◽  
pp. 421-426
Author(s):  
Daria Zhemchuzhnikova ◽  
Rustam Kaibyshev
Keyword(s):  
Grain Size ◽  
Impact Toughness ◽  
Impact Energy ◽  
Coarse Grained ◽  
Fine Grained ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Coarse Grained State ◽  
Hot Rolled ◽  
The Impact

Analysis of the absorbed impact energy of an Al-Mg-Sc alloy after different thermo-mechanical processing routes was investigated between-196°C and 20°C. The material with a grain size of ∼ 22 μm in cast condition and with an average grain size of 0.7 μm produced by was produced by equal-channel angular pressing (ECAP) exhibits well-defined ductile-brittle transition in the temperature interval-60...-100°C, however, even at-196°C the value impact energy of fine-grained alloy is higher by a factor of 2 in comparison with coarse-grained state. The impact toughness of the hot rolled alloy linearly decreases with decreasing temperature. The influence of different microstructures on impact toughness and fracture behavior of alloy is discussed.

Mechanical Properties of Girth Weld with Different Butt Materials Severed for Natural Gas Station

2019 ◽  
Vol 944 ◽  
pp. 821-827
Author(s):  
Jun Jie Ren ◽  
Wei Feng Ma ◽  
Xue Liang He ◽  
An Qi Chen ◽  
Jin Heng Luo ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Wall Thickness ◽  
Impact Energy ◽  
Weld Seam ◽  
Coarse Grained ◽  
Lower Grade ◽  
Straight Pipe ◽  
Bending Load ◽  
Girth Welds ◽  
The Impact

Weld samples imitating the inservice girth welds in station (L245 straight pipe jointed to WPHY-70 tee joint and L415MB straight pipe jointed to WPHY-80 tee joint) were prepared. Tensile, bending, impact toughness and hardness of the joints were investigated. Results show that under tensile or bending load, failure occurred from the side with lower grade and smaller wall thickness. Relatived to the lower grade side, the weld seam is strong match. Significant change of impact toughness can be found in weld seam center and the heat affected zones (HAZ). The impact energy of seam center is the lowest in the weld joint. The impact energy show a trend of increase from seam center to base metal. In HAZ zone, impact toughness of the fusion line is the lowest. Impact toughness of higher grade side is higher than that of the lower grade side. Hardness of positions in HAZ zones are different distinctly. From coarse grained region to fine grained region, the hardness decrease. For the in-station girth welds jointed with different materials, lower grade and samller wall thickness side should be intensive monitored.

Cavitation Behavior of Ultra-Fine Grained Ti-6Al-4V Alloy Produced by Equal-Channel Angular Pressing

2007 ◽  
Vol 551-552 ◽  
pp. 621-626
Author(s):  
Young Gun Ko ◽  
Yong Nam Kwon ◽  
Jung Hwan Lee ◽  
Dong Hyuk Shin ◽  
Chong Soo Lee
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Equal Channel Angular Pressing ◽  
Cavity Growth ◽  
Rate Sensitivity ◽  
Theoretical Models ◽  
Coarse Grained ◽  
Fine Grained ◽  
Angular Pressing ◽  
Cavitation Behavior

Cavitation behavior during superplastic flow of ultra-fine grained (UFG) Ti-6Al-4V alloy was established with the variation of grain size and misorientation. After imposing an effective strainup to 8 via equal-channel angular pressing (ECAP) at 873 K, alpha-phase grains were markedly refined from 11 μm to ≈ 0.3 μm, and misorientation angle was increased. Uniaxial-tension tests were conducted for initial coarse grained (CG) and two UFG alloys (ε = 4 and 8) at temperature of 973 K and strain rate of 10-4 s-1. Quantitative measurements of cavitation evidenced that both the average size and the area fraction of cavities significantly decreased with decreasing grain size and/or increasing misorientation. It was also found that, when compared to CG alloy, cavitation as well as diffused necking was less prevalent in UFG alloys, which was presumably due to the higher value of strain-rate sensitivity. Based on the several theoretical models describing the cavity growth behavior, the cavity growth mechanism in UFG alloys was suggested.

Grain Refinement of Copper Alloys by Equal Channel Angular Pressing

2004 ◽  
Vol 449-452 ◽  
pp. 177-180 ◽  
Author(s):  
Cha Yong Lim ◽  
Jae Hyuck Jung ◽  
Seung Zeon Han
Keyword(s):  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Copper Alloys ◽  
Metallic Materials ◽  
Fine Grained ◽  
Angular Pressing ◽  
Fine Grain ◽  
Transmission Electron ◽  
Ultrafine Grained ◽  
Average Grain Size

The equal channel angular pressing (ECAP) is one of the methods to refine the grain size of metallic materials. This study investigates the effect of ECAP process on the formation of the fine grain size in oxygen free Cu and Cu alloys. The average grain size has been refined from 150 µm before ECAP to 300 nm. Microstructure was analyzed by transmission electron micrography (TEM). The diffraction pattern of the selected area confirmed the formation of ultrafine-grained structure with high angle grain boundaries after 8 cycles of ECAP. Mechanical properties such as microhardness and tensile properties of the ultra-fine grained copper materials have been investigated.

scholarly journals Impact of Equal Channel Angular Pressing on Mechanical Behavior and Corrosion Resistance of Hot-Rolled Ti-2Fe-0.1B Alloy

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5117
Author(s):  
Yanhuai Wang ◽  
Xin Li ◽  
I. V. Alexandrov ◽  
Li Ma ◽  
Yuecheng Dong ◽  
...  
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Titanium Alloy ◽  
Mechanical Behavior ◽  
Equal Channel Angular Pressing ◽  
Hot Rolling ◽  
Low Cost ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Hot Rolled

In the present study, the unique bimodal grain size distribution microstructure with the ultrafine substrate and embedded macro grains was fabricated by a traditional hot-rolling process in a novel low-cost Ti-2Fe-0.1B titanium alloy, which possesses a good combination of strength (around 663 MPa) and ductility (around 30%) without any post heat treatment. Meanwhile, the mechanical behavior and corrosion resistance of hot-rolled Ti-2Fe-0.1B alloy after equal channel angular pressing (ECAP) deformation were studied. Results indicated that the average grain size decreased to 0.24 μm after 4 passes ECAP deformation, which led to the enhancement of tensile strength to around 854 MPa and good ductility to around 15%. In addition, corrosion resistance was also improved after ECAP due to the rapid self-repairing and thicker passivation film. Our study revealed that the novel low-cost titanium alloy after hot-rolling and ECAP could be used instead of Ti-6Al-4V in some industrial applications due to similar mechanical behavior and better corrosion resistance.

scholarly journals Optimization of PWHT of Simulated HAZ Subzones in P91 Steel with Respect to Hardness and Impact Toughness

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1215 ◽  
Author(s):  
Gorazd Lojen ◽  
Tomaž Vuherer
Keyword(s):  
Impact Toughness ◽  
Elevated Temperatures ◽  
Thermal Power ◽  
Post Weld Heat Treatment ◽  
Coarse Grained ◽  
Target Range ◽  
Fine Grained ◽  
Creep Resistant Steels ◽  
The Impact ◽  
Weld Heat

Appropriate post weld heat treatment (PWHT) is usually obligatory when creep resistant steels are welded for thermal power plant components that operate at elevated temperatures for 30-40 years. The influence of different PWHTs on the microstructure, hardness, and impact toughness of simulated heat affected zone (HAZ) subzones was studied. Thereby, coarse grained HAZ, two different fine grained HAZ areas, and intercritical HAZ were subjected to 20 different PWHTs at temperatures 740–800 °C and durations 0.5–8 h. It was found that the most commonly recommended PWHT, of 3 h or less at 760 °C, is insufficient with respect to the hardness and impact toughness of coarse grained HAZ. To obtain a Vickers hardness ≤ 265 HV and impact toughness at least equal to the impact toughness of the base metal (192 J) in the coarse grained HAZ, it took 8 h at 740 °C, 4 h at 760 °C, more than 1 h at 780 °C, and 0.5 h and 800 °C. Even after 8 h at 800 °C, mechanical properties were still within the target range. The most recommendable post weld heat treatments at 780 °C for 1.2–2 h or at 760 °C for 3–4 h were identified. All specimens subjected to these treatments exhibited appropriate hardness, impact toughness, and microstructure.

The Impact of Grain Size on Oxidation Behavior of TP304H Austenitic Stainless Steel at High Temperature in Air

2011 ◽  
Vol 117-119 ◽  
pp. 990-994
Author(s):  
Wei Wei ◽  
Zhi Wu Wang ◽  
Mao Lin Liu
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Oxide Scale ◽  
Grain Refinement ◽  
Coarse Grained ◽  
X Ray ◽  
Fine Grained ◽  
Different Grain Size ◽  
The Impact

Exposed to 650°C air, TP304H stainless steel with two different grain size was oxidized at this temperature. At the meantime, comparison of their oxidation was through the oxidation kinetics curves and analysis of the morphology and composition of oxide scale which conducted by SEM and X-ray. The results showed that the oxidation rate of TP304H stainless steel was slowed down by grain refinement and oxide scale of fine-grained TP304H steel was thinner than that of coarse-grained steel. The nucleation and the growth of nuclei of coarse-grained oxide scale were more rapid. In addition, the grain refinement of austenitic stainless steel accelerated the diffusivity of Cr and made for the formation of dense and continuous oxide scale, so that the oxidation of stainless steel can be effectively inhabited.

Texture of Al-Cu Alloys Deformed by ECAP

2005 ◽  
Vol 495-497 ◽  
pp. 851-856 ◽  
Author(s):  
Jan Kuśnierz ◽  
Marie Helene Mathon ◽  
Thierry Baudin ◽  
Zdzislaw Jasieński ◽  
Richard Penelle
Keyword(s):  
Grain Size ◽  
Aluminium Alloys ◽  
Superplastic Forming ◽  
Orientation Distribution ◽  
Coarse Grained ◽  
Fine Grained ◽  
Angular Pressing ◽  
Cu Alloys ◽  
Super Plastic ◽  
Short Time

Materials of ultra-fine grained microstructure (sub-micrometer grain size) exhibit large strength, hardness and ductility and also the increased toughness in comparison with conventional coarse-grained ones. In these materials also the super-plastic flow at lower temperatures is observed. This behaviour may be interesting when aluminium alloys like AlCuZr, used in superplastic forming, are considered. In the paper, the methods of preparing such materials by equal-channel angular pressing (ECAP) is proposed and the texture analysis, based on neutron diffraction pole figure measurements and calculated orientation distribution function of two alloys AlCu4SiMn and AlCu5AgMgZr is discussed. The influence of short time recrystallization is discussed in relation with TEM and SEM observations.

Effect of grain size and mechanical processing on the dielectric properties of BaTiO3

1995 ◽  
Vol 10 (6) ◽  
pp. 1418-1423 ◽  
Author(s):  
B.W. Lee ◽  
K.H. Auh
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Dielectric Properties ◽  
Domain Switching ◽  
External Pressure ◽  
Coarse Grained ◽  
One Dimensional ◽  
Fine Grained ◽  
Average Grain Size ◽  
Coarse Grained Material

Dielectric properties of polycrystalline BaTiO3 ceramics having grain sizes of 1 to 40 μm have been studied. Fine-grained ceramic BaTiO3 of 1 μm average grain size has 90°domains and has shown higher dielectric constant, lower ferroelectric transition temperature (Tc), and lower transition energy than coarser-grained material. 90°domain switching was preferentially produced in the fine-grained BaTiO3 as a result of abrasion. For the fine-grained BaTiO3, the dielectric constant decreased with one-dimensional pressure, whereas, for the coarse-grained material, the dielectric constant increased before decreasing with the pressure. The one-dimensional pressure resulted in increased Tc of both the fine- and coarse-grained BaTiO3, with the effect being the greatest for the coarse-grained material. The relationship between these results and internal stress, and the effect of external pressure imposed on internally stressed lattice, were discussed.

Microstructure–Property Relationship in 22mm Thick X80 Coil Skelp

2010 ◽  
Author(s):  
M. Liebeherr ◽  
N. Bernier ◽  
D. Le`bre ◽  
N. Ilic´ ◽  
D. Quidort
Keyword(s):  
Grain Size ◽  
Impact Toughness ◽  
Electron Backscatter Diffraction ◽  
Bainitic Ferrite ◽  
Hot Strip Mill ◽  
Low Carbon ◽  
Welded Pipe ◽  
Hot Rolled ◽  
Backscatter Diffraction ◽  
The Impact

The progress in the development of heavy gauge X80 linepipe steel on coil at ArcelorMittal was recently rewarded with a 6000 ton commercial order for the production of 21.6mm wall thickness spiral welded pipe. The further product development is concentrating on the improvement of the impact toughness at low temperatures. Research is currently focussing on the relationship between the mechanical properties and the microstructure of the steels. In the present study, two industrially hot rolled X80 steels with thickness 21.6mm were investigated. The steels had the same chemical composition but were processed with different parameter sets in the hot strip mill. The two resulting low-carbon bainitic microstructures were composed predominantly of quasi-polygonal ferrite and globular bainitic ferrite / bainitic ferrite, respectively. Emphasis of the microstructure and property characterisation was laid on through-thickness gradients of grain size, hardness, texture, impact toughness and tensile properties. Accordingly, the materials were characterised at different positions in the thickness. Grain size and texture were determined by means of Electron Backscatter Diffraction (EBSD). Sub-size Charpy as well as sub-thickness tensile test specimens were taken at different positions in the cross section. The results show that the link between microstructure and properties is not at all obvious. The influence of mean grain size, grain size distribution and texture is discussed in detail.

scholarly journals Effect of ECAP on the Microstructure and Mechanical Properties of a Rolled Mg-2Y-0.6Nd-0.6Zr Magnesium Alloy

Crystals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 586 ◽  
Author(s):  
Shi ◽  
Li ◽  
Hu ◽  
Tan ◽  
Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Room Temperature ◽  
High Strength ◽  
Electron Backscattered Diffraction ◽  
Bar Rolling ◽  
Fine Grained ◽  
Angular Pressing ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size

A fine-grained Mg-2Y-0.6Nd-0.6Zr alloy was processed by bar-rolling and equal-channel angular pressing (ECAP). The effect of ECAP on the microstructure and mechanical properties of rolled Mg-2Y-0.6Nd-0.6Zr alloy was investigated by optical microscopy, scanning electron microscopy, electron backscattered diffraction and a room temperature tensile test. The results show that the Mg-2Y-0.6Nd-0.6Zr alloy obtained high strength and poor plasticity after rolling. As the number of ECAP passes increased, the grain size of the alloy gradually reduced and the texture of the basal plane gradually weakened. The ultimate tensile strength of the alloy first increased and then decreased, the yield strength gradually decreased, and the plasticity continuously increased. After four passes of ECAP, the average grain size decreased from 11.2 µm to 1.87 µm, and the alloy obtained excellent comprehensive mechanical properties. Its strength was slightly reduced compared to the as-rolled alloy, but the plasticity was greatly increased.

Sign in / Sign up

Export Citation Format

Share Document