scholarly journals Comparison on Tensile Characteristics of Plain C–Mn Steel with Ultrafine Grained Ferrite/Cementite Microstructure and Coarse Grained Ferrite/Pearlite Microstructure

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2309
Author(s):  
Yan Tian ◽  
Mingchun Zhao ◽  
Wenjian Liu ◽  
Jimou Zhang ◽  
Min Zhang ◽  
...  
Keyword(s):  
Uniform Elongation ◽  
Tensile Tests ◽  
Total Elongation ◽  
Microstructural Change ◽  
Coarse Grained ◽  
Lower Yield ◽  
Thermal Component ◽  
Ultrafine Grained ◽  
Athermal Component ◽  
Mn Steel

This work investigated the tensile characteristics of plain C–Mn steel with an ultrafine grained ferrite/cementite (UGF/C) microstructure and coarse-grained ferrite/pearlite (CGF/P) microstructure. The tensile tests were performed at temperatures between 77 K and 323 K. The lower yield and the ultimate tensile strengths were significantly increased when the microstructure was changed from the CGF/P to the UGF/C microstructures, but the total elongation and the uniform elongation decreased. A microstructural change from the CGF/P microstructure to the UGF/C microstructure had an influence on the athermal component of the lower yield and the ultimate tensile strengths but not on the thermal component. The UGF/C microstructure with a higher carbon content provided a higher strength without losing ductility because cementite particles restrained necking.

An Analysis of Strength and Ductility of Ultrafine Grained Al Alloys

2009 ◽  
Vol 633-634 ◽  
pp. 165-177 ◽  
Author(s):  
R. Kapoor ◽  
P.S. De ◽  
Rajiv S. Mishra
Keyword(s):  
Uniform Elongation ◽  
Large Fraction ◽  
Rate Sensitivity ◽  
Total Elongation ◽  
Processing Technique ◽  
Equivalent Strain ◽  
Al Alloys ◽  
Coarse Grained ◽  
Analytical Prediction ◽  
Ultrafine Grained

This paper brings together and compares data of various ultrafine grained (UFG) Al alloys processed through different routes. In general, the trend of decreasing ductility with increasing strength was observed for the UFG alloys. As compared to the coarse grained (CG) alloys, the UFG alloys show a lower ductility, a lower extent of work-hardening and a lower uniform elongation. Unlike the CG alloys, which show a large fraction of uniform to total elongation, in UFG alloys this fraction varies with processing technique. It is shown here that aging of some UFG Al alloys improves ductility. Further, it is shown that increasing the equivalent strain of pre-deformation increases ductility. From this it was inferred that high angle grain boundaries have an important influence on ductility. The variation of ductility with strain rate sensitivity has been found to match both the analytical prediction as well as data of various materials.

scholarly journals New Approach In The Properties Evaluation Of Ultrafine-Grained OFHC Copper

2015 ◽  
Vol 60 (2) ◽  
pp. 605-614 ◽  
Author(s):  
T. Kvačkaj ◽  
A. Kováčová ◽  
J. Bidulská ◽  
R. Bidulský ◽  
R. Kočičko
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Wear Behaviour ◽  
Ofhc Copper ◽  
Strain Rates ◽  
Ultrafine Grained ◽  
Reduction Of Area ◽  
Pin On Disk

AbstractIn this study, static, dynamic and tribological properties of ultrafine-grained (UFG) oxygen-free high thermal conductivity (OFHC) copper were investigated in detail. In order to evaluate the mechanical behaviour at different strain rates, OFHC copper was tested using two devices resulting in static and dynamic regimes. Moreover, the copper was subjected to two different processing methods, which made possible to study the influence of structure. The study of strain rate and microstructure was focused on progress in the mechanical properties after tensile tests. It was found that the strain rate is an important parameter affecting mechanical properties of copper. The ultimate tensile strength increased with the strain rate increasing and this effect was more visible at high strain rates$({\dot \varepsilon} \sim 10^2 \;{\rm{s}}^{ - 1} )$. However, the reduction of area had a different progress depending on microstructural features of materials (coarse-grained vs. ultrafine-grained structure) and introduced strain rate conditions during plastic deformation (static vs. dynamic regime). The wear behaviour of copper was investigated through pin-on-disk tests. The wear tracks examination showed that the delamination and the mild oxidational wears are the main wear mechanisms.

Grain Refinement and Deformation Behavior of Ultrafine Grained Pd and Pd-Ag Alloys Produced by HPT

2008 ◽  
Vol 584-586 ◽  
pp. 182-187
Author(s):  
Lilia Kurmanaeva ◽  
Yulia Ivanisenko ◽  
J. Markmann ◽  
Ruslan Valiev ◽  
Hans Jorg Fecht
Keyword(s):  
Mechanical Properties ◽  
Deformation Behavior ◽  
Materials Science ◽  
High Pressure Torsion ◽  
Uniform Elongation ◽  
Grain Structure ◽  
Coarse Grained ◽  
Ultrafine Grain ◽  
Ultrafine Grained ◽  
Ultrafine Grain Structure

Investigations of mechanical properties of nanocrystalline (nc) materials are still in interest of materials science, because they offer wide application as structural materials thanks to their outstanding mechanical properties. NC materials demonstrate superior hardness and strength as compared with their coarse grained counterparts, but very often they possess a limited ductility or show low uniform elongation due to poor strain hardening ability. Here, we present the results of investigation of the microstructure and mechanical properties of nc Pd and Pd-x%Ag (x=20, 60) alloys. The initially coarse grained Pd-x% Ag samples were processed by high pressure torsion, which resulted in formation of homogenous ultrafine grain structure. The increase of Ag contents led to the decrease of the resulted grain size and change in deformation behavior, because of decreasing of stacking fault energy (SFE). The samples with larger Ag contents demonstrated the higher values of hardness, yield stress and ultimate stress. Remarkably the uniform elongation had also increased with increase of strength.

Ultrafine-Grained Steel Produced by Warm Rolling and Annealing of Lath Martensite

2010 ◽  
Vol 667-669 ◽  
pp. 863-866
Author(s):  
Xin Zhao ◽  
Xiao Ling Yang
Keyword(s):  
Lath Martensite ◽  
Tensile Tests ◽  
Total Elongation ◽  
Optical Microscope ◽  
Warm Rolling ◽  
Steel Plates ◽  
Transmission Electron ◽  
Hardness Tests ◽  
Ultrafine Grained ◽  
Ultrafine Grained Steel

Steel plates with lath martensite microstructure were rolled up to 68% reduction at 673 K and then annealed at 473-973 K. The microstructure evolution was studied by using an optical microscope and a transmission electron microscopy. And the properties were investigated by using tensile tests and hardness tests. Results show that ultrafine grains + nano-carbides are obtained in the steel plates. The specimen annealed at 823 K has a good combination of strength and ductility. The tensile strength and total elongation are 1028 MPa and 7.2%, respectively. And the hardness is 338 Hv.

Study on High Temperature Creep Test of P92 Material Based on the Minimally Invasive Technique

2017 ◽  
Vol 734 ◽  
pp. 159-167
Author(s):  
Chao Zhou ◽  
Jun Liang ◽  
Bin Wang
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Yield Strength ◽  
Creep Test ◽  
Uniform Elongation ◽  
Tensile Tests ◽  
Total Elongation ◽  
Invasive Technique ◽  
P92 Steel ◽  
Power Law Creep

The tensile and creep properties of P92 steel have been studied using a precision tensile and creep test machines for miniature and conventional specimens under various stress level at 625°C. The results showed that the data stability of miniature plate specimens is high whether at room or high temperature tensile tests. Compared with the conventional plate specimens, tensile strength, yield strength and total elongation is slightly lower, the uniform elongation is higher for miniature plate specimens at room temperature. By contrast, the tensile strength and uniform elongation is slightly higher, and the yield strength and total elongation is lower at high temperature. Besides, there had similar creep curves between miniature and conventional specimens, and the creep rupture time and minimum creep rate are closer under the same stress. By comparing the power law creep index and damage tolerance factor at the second creep stage, it can be derived that the creep mechanism is identical for the micro and conventional specimens, which is controlled by the dislocation movement.

Ultrafine Grained Dual Phase Steels Fabricated by Equal Channel Angular Pressing

2006 ◽  
Vol 503-504 ◽  
pp. 447-454 ◽  
Author(s):  
Dong Hyuk Shin ◽  
Woo Gyeom Kim ◽  
Jung Yong Ahn ◽  
Kyung Tae Park ◽  
Yong Suk Kim
Keyword(s):  
Strain Hardening ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Intercritical Annealing ◽  
Total Elongation ◽  
Coarse Grained ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Angular Pressing ◽  
Ultrafine Grained

Ultrafine grained (UFG) ferrite-martensite dual phase steels were fabricated by equal channel angular pressing and subsequent intercritical annealing. Their room temperature tensile properties were examined and compared to those of coarse grained counterpart. The formation of UFG martensite islands of ~ 1 μm was not confined to the former pearlite colonies but they were uniformly distributed throughout UFG matrix. The strength of UFG dual phase steels was much higher than that of coarse grained counterpart but uniform and total elongation were not degraded. More importantly, unlike most UFG metals showing negligible strain hardening, the present UFG dual phase steels exhibited extensive rapid strain hardening.

Mechanical Properties of Fine-Grained and Ultrafine-Grained Ti-6Al-4V with Equiaxed and Bimodal Microstructures

2016 ◽  
Vol 879 ◽  
pp. 344-349 ◽  
Author(s):  
Yan Chong ◽  
Nobuhiro Tsuji
Keyword(s):  
Mechanical Properties ◽  
Thermomechanical Processing ◽  
Uniform Elongation ◽  
True Strain ◽  
Tensile Tests ◽  
Initial Microstructure ◽  
Equiaxed Microstructure ◽  
Fine Grained ◽  
Ultrafine Grained ◽  
Mean Grain Size

With the purpose of fabricating equiaxed and bimodal Ti-6Al-4V alloy with different grain/primary α (αp) sizes, thermomechanical processing and additional annealing were carried out on samples with martensite initial microstructure. Deformation at 700°C with a strain rate of 0.01s-1 to a true strain of 0.8 could effectively break the martensite initial microstructure into ultrafine-grained (UFG) equiaxed microstructure (mean grain size of 0.51μm) with reasonable uniformity. Subsequent annealing at 930°C with different periods were conducted to change the equiaxed microstructure into bimodal microstructures. The holing time proved to be more critical than heating rate for determining the αp size. An UFG bimodal Ti-6Al-4V with the average αp size of 0.55μm was successfully obtained for the first time by annealing the UFG equiaxed Ti-6Al-4V at 930°C for 2 seconds. The mechanical properties of the equiaxed and bimodal Ti-6Al-4V with different grain/αp sizes were evaluated by tensile tests at room temperature. The bimodal Ti-6Al-4V showed superior balance between strength and uniform elongation than that of the equiaxed Ti-6Al-4V. Moreover, the uniform elongation in the bimodal Ti-6Al-4V was nearly unaffected by reduction of the αp size.

High Strength Microscrew with Ultrafine Grained Structure

2014 ◽  
Vol 783-786 ◽  
pp. 2695-2700
Author(s):  
Shiro Torizuka ◽  
Eijiro Muramatsu
Keyword(s):  
Uniform Elongation ◽  
Steel Wire ◽  
High Strength ◽  
Tensile Tests ◽  
Low Carbon ◽  
Ultrafine Grained Structure ◽  
Bainitic Steels ◽  
Ultrafine Grained ◽  
Reduction In Area ◽  
Ultrafine Grained Steel

While uniform elongation is a measure of ductility of the material, reduction in area in tensile tests is also an important measure of ductility. It was found that the reduction in area - tensile strength balance is far better than the conventional ferrite+pearlite steels and even superior to martensitic and bainitic steels. Formability of ultrafine-grained steel is examined by applying to form a M1.7 micro screw using these ultrafine-grained steels. Screws are formed through the process of cold heading and rolling. Relationship between cold heading, rolling, uniform elongation and reduction in area are investigated to clarify the formability of ultrafine-grained steels. Low-carbon ultrafine-grained steel has excellent cold headability and favorable rolling properties, i.e., excellent formability. Reduction in area is a measure to determine formability on cold heading. Ultrafine grained steel wire with length of several hundred meter were developed with the technology of warm continuous multi-directional rolling. This wire also have a good formability which can form microscrews. High strength microscrew with ultrafine grained structure was obtained.

Preparation and Mechanical Properties of Ultrafine Grained Metals

1990 ◽  
Vol 195 ◽  
Author(s):  
B. Gunther ◽  
A. Baalmann ◽  
H. Weiss
Keyword(s):  
Yield Strength ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Strengthening Effect ◽  
Ultrafine Grained ◽  
Concurrent Processes ◽  
Evaporation Technique ◽  
Cold Worked ◽  
20 Nm ◽  
Coble Creep

ABSTRACTUltrafine—grained polycrystalline metallic components (Cu, Au, Fe) have been prepared by means of the inert gas evaporation technique combined with an integrated uniaxial cold compaction device. The average grain sizes ranaed typically from 20 nm to about 100 nm. The microstructure and Imourity content of the as-pressed samples have been investigated by means of TEM and AES, respectively. The yield strength of ultrafine (30 nm) grained Cu specimens obtained in tensile tests compares well with respective values for heavily cold—worked coarse grained copper. Al slight heat treatment (150ºC/30min) improves the strain—to—fracture at slightly reduced yield strength values. The results are discussed within the picture of two concurrent processes determining the strength of ultrafine grained metals: Coble creep vs. grain boundary strengthening effect.

Microstructure and Mechanical Properties of an Ultrafine Grained Medium-Mn Steel

2018 ◽  
Vol 385 ◽  
pp. 308-313 ◽  
Author(s):  
Vladimir Torganchuk ◽  
Dmitri A. Molodov ◽  
Andrey Belyakov ◽  
Rustam Kaibyshev
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Total Elongation ◽  
Manganese Steel ◽  
Two Phase ◽  
Microstructure And Mechanical Properties ◽  
Ultrafine Grained ◽  
Medium Manganese Steel ◽  
Medium Mn Steel ◽  
Mn Steel

The effect of cold working followed by annealing on the development of ultrafine grained microstructure and mechanical properties of an Fe-12%Mn-0.6%C-1.5%Al medium-manganese steel was studied. The steel was cold rolled with intermediate annealings and then annealed at 873 K or 923 K for 30 min. The yield strength and total elongation of the Fe-12Mn-0.6C-1.5Al steel after cold rolling were 1200 MPa and 14%, respectively. The heat treatments resulted in the formation of two phase (austenite-ferrite) ultrafine grained microstructures with average grain sizes of 0.9 to 1.2 μm, depending on the annealing temperature. The annealed ultrafine grained steel samples exhibit the yield strength in the range of 800-950 MPa, the ultimate tensile strength in the range of 1150-1200 MPa, and total elongation of 12% to 19%.

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