Effect of Ultra-Fast Cooling Rate on the Microstructure and Mechanical Properties of High Strength Cold-Rolled Sheet under Continuous Annealing

2018 ◽  
Vol 913 ◽  
pp. 311-316
Author(s):  
Kai Zhang ◽  
Ren Bo Song ◽  
Feng Gao ◽  
Wen Jie Niu ◽  
Chi Chen
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Cooling Rate ◽  
High Strength ◽  
Rolled Sheet ◽  
Cooling Rates ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size ◽  
Cold Rolled ◽  
Fast Cooling

The effect of different fast cooling rates on the microstructure and mechanical properties of the V and Ti microalloyed high strength cold-rolled sheet was studied under laboratory conditions. Five different fast cooling rates were set up as 20°C/s, 50°C/s, 200°C/s, 500°C/s and 1000°C/s, respectively. Optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the microstructure, and the mechanical properties were also tested. The results showed that with the increase of fast cooling rate from 20°C/s to 1000°C/s, the grains of martensite and ferrite were finer, and the average grain size of both martensite and ferrite decreased from 7.7μm to 3.9μm. The proportion of ferrite in the two phases decreased while that of the martensite increased from 25.7% to 62.1%. The morphology of martensite tended to be lath, and the density of dislocation in the ferrite grains nearby the martensite gradually increased. With cooling rate rising from 20°C/s to 1000°C/s, the yield strength of the experimental steel increased from 381MPa to 1074MPa, and the tensile strength increased from 887MPa to 1199MPa. And the elongation decreased from 14.2% to 7.2%, and the product of strength and elongation decreased from 12.6GPa·% to 8.6GPa·%.

Effects of Thermo-Mechanical Process on the Microstructure and Mechanical Properties of Low Carbon HSLA Steels

2006 ◽  
Vol 15-17 ◽  
pp. 786-791 ◽  
Author(s):  
J.S. Kang ◽  
Y. Huang ◽  
C.W. Lee ◽  
Chan Gyung Park
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Cooling Rate ◽  
High Strength ◽  
Nucleation Site ◽  
Polygonal Ferrite ◽  
Low Alloy Steels ◽  
Low Carbon ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size

Effects of deformation at austenite region and cooling rate on the microstructure and mechanical properties of low carbon (0.06 wt. % C) high strength low alloy steels have been investigated. Average grain size decreased and polygonal ferrite transformation promoted with increasing deformation amount at austenite region due to increase of ferrite nucleation site. Microstructure was also influenced by cooling rate resulting in the development of a mixture of fine polygonal ferrite and acicular ferrite at 10°C/s cooling rate. Discontinuous yielding occurred in highly deformed specimen due to the formation of polygonal ferrite. However, small grain size of highly deformed specimen caused lower ductile-to-brittle transition temperature than slightly deformed specimen.

scholarly journals Effect of Nano-Y2O3 Content on Microstructure and Mechanical Properties of Fe18Cr Films Fabricated by RF Magnetron Sputtering

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1754
Author(s):  
Bang-Lei Zhao ◽  
Le Wang ◽  
Li-Feng Zhang ◽  
Jian-Gang Ke ◽  
Zhuo-Ming Xie ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Magnetron Sputtering ◽  
Photoelectron Spectroscopy ◽  
Synergetic Effect ◽  
Rf Magnetron Sputtering ◽  
Dispersion Phase ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size ◽  
Y2o3 Content

In this work, FeCr-based films with different Y2O3 contents were fabricated using radio frequency (RF) magnetron sputtering. The effects of Y2O3 content on their microstructure and mechanical properties were investigated through scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), inductive coupled plasma emission spectrometer (ICP) and a nanoindenter. It was found that the Y2O3-doped FeCr films exhibited a nanocomposite structure with nanosized Y2O3 particles uniformly distributed into a FeCr matrix. With the increase of Y2O3 content from 0 to 1.97 wt.%, the average grain size of the FeCr films decreased from 12.65 nm to 7.34 nm, demonstrating a grain refining effect of Y2O3. Furthermore, the hardness of the Y2O3-doped FeCr films showed an increasing trend with Y2O3 concentration, owing to the synergetic effect of dispersion strengthening and grain refinement strengthening. This work provides a beneficial guidance on the development and research of composite materials of nanocrystalline metal with a rare earth oxide dispersion phase.

Microstructure and Mechanical Properties of a Multi-Modal Al Alloy with High Strength

2013 ◽  
Vol 745-746 ◽  
pp. 286-292
Author(s):  
Xiao Ning Hao ◽  
Rui Xiao Zheng ◽  
Li Rong Hao ◽  
Han Yang ◽  
Chao Li Ma
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Alloy Powder ◽  
Mechanical Test ◽  
High Strength ◽  
Bulk Sample ◽  
Coarse Grained ◽  
Al Alloy ◽  
Consolidation Process ◽  
Microstructure And Mechanical Properties

Nanocrystalline (NC) Al alloy powder was fabricated by milling 2024 Al alloy powder and Fe-based metallic glass (FMG) particles. The NC Al alloy powder was consolidated into bulk sample by adding a part of atomized coarse-grained (CG) 2024 alloy powder. The microstructure and mechanical properties of powder and consolidated bulk materials were examined by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and mechanical test. It revealed that the FMG particles were uniformly distributed in the NC aluminum alloy powder. In the consolidation process, the grain size increased, and Al2CuMg phase precipitated. The multi-modal Al alloy by consolidation of FMG particles, NC and CG powder, exhibited higher yield strength up to 517 MPa and better plasticity in comparison to the samples without CG powder.

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.

Microstructure and Mechanical Properties of AA5483 after Combination of ECAP and Hydrostatic Extrusion SPD Processes

2014 ◽  
Vol 59 (1) ◽  
pp. 163-166 ◽  
Author(s):  
M. Kulczyk ◽  
J. Skiba ◽  
W. Pachla
Keyword(s):  
Mechanical Properties ◽  
Salt Water ◽  
True Strain ◽  
High Strength ◽  
Tensile Tests ◽  
Hydrostatic Extrusion ◽  
Angular Pressing ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size ◽  
Marine Applications

Abstract Al-Mg alloys of the 5xxx series are strain hardenable and have moderately high strength, excellent corrosion resistance even in salt water, and very high toughness even at cryogenic temperatures to near absolute zero, which makes them attractive for a variety of applications, e.g. in systems exploited at temperatures as low as -270°C, and marine applications. The present study is concerned with the effect of a combination of 2 processes, which generate serve plastic deformation (SPD), equal channel angular pressing (ECAP) and hydrostatic extrusion (HE), on the microstructure and mechanical properties of an alloy that contain Al and Mg. The alloy was subjected to multi-pass ECAP followed by cumulative HE with a total true strain of 5.9. The microstructure of SPD samples was evaluated by transmission and scanning electron microscopy. The mechanical properties were determined by tensile tests and microhardness measurements. The combination of the two processes gave a uniform nanostructure with an average grain size of 70nm. The grain refinement taking place during the SPD processing resulted in the increase of the mechanical strength by 165% (YS) with respect to that of the material in the as- received state. The experiments have shown that the combination of HE and ECAP permits producing homogeneous nanocrystalline materials of large volumes.

scholarly journals Influence of the cooling behaviour on mechanical properties of carbon fibre-reinforced thermoplastic/metal laminates

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Camilo Zopp ◽  
Daisy Nestler ◽  
Nadine Buschner ◽  
Carola Mende ◽  
Sven Mauersberger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Fibre ◽  
Cooling Rate ◽  
Thermoplastic Polyurethane ◽  
Polyamide 6 ◽  
Shear Properties ◽  
Cooling Rates ◽  
Hybrid Laminates ◽  
Fast Cooling ◽  
Interlaminar Shear

For several years, thermoplastic hybrid laminates form a new class in the field of material compounds. These laminates consist of fibre-reinforced plastic prepregs and metal layers in alternating order. Compared to conventional thermosetting multilayer composites, these laminates are suitable for large-scale production and can be manufactured with significantly reduced cycle times in the thermoforming process.  In the framework of this contribution, the influence of the cooling rate of carbon fibre-reinforced thermoplastic composites and hybrid laminates was investigated with regard to crystallinity and the resulting mechanical properties. Polyamide 6 and thermoplastic polyurethane as matrix systems were examined, in particular.Additionally, the differential scanning calorimetry was used in order to investigate the influence of the cooling rate on the crystallisation behaviour. It could be determined that the cooling rate has a limited influence on the crystallisation of polyamide 6 and this influences the mechanical properties. Furthermore, a reliance of process parameters on the characteristics profile of composite materials and material compounds with thermoplastic polyurethane could be identified. Depending on process conditions, tensile, bending, and interlaminar shear properties fluctuate up to 20 % in fibre-reinforced laminates and up to 32 % in hybrid laminates. Moderate to fast cooling rates result in optimum mechanical characteristics of tensile properties in fibre-plastic-compounds. Fast to very fast cooling rates are advisable for bending and interlaminar shear properties. Highest tensile and bending characteristics are achieved in hybrid laminates by using fast to very fast cooling rates, while interlaminar shear properties tend to be highest in slow to moderate cooling rates.

Effect of Continuous Annealing Temperature on Microstructure and Mechanical Properties of a High Strength Cold-Rolled DP980 Steel

2016 ◽  
Vol 879 ◽  
pp. 2144-2149
Author(s):  
Kai Zhou ◽  
Ying Zou ◽  
Yun Bo Xu ◽  
Zhi Ping Hu ◽  
Xiao Dong Tan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Uniaxial Tensile ◽  
Continuous Annealing ◽  
Moderate Increase ◽  
Fracture Elongation ◽  
Microstructure And Mechanical Properties ◽  
Cold Rolled

Continuous annealing processes were applied to a 980MPa cold-rolled dual phase steel (Fe-0.11C-2.5Mn-0.5Si-0.4Cr) and the effect of continuous annealing temperature on microstructure and mechanical properties was investigated. The microstructures were observed and analyzed by optical microscopy (OM), scanning electron microscopy (SEM), electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM). The mechanical properties were measured by uniaxial tensile tests. The results revealed that the steel is composed of a certain percentage of ferrite, martensite and perhaps a small amount of retained austenite as well. As the annealing temperature increased, the volume fraction of martensite reached to 67% from 48% and the morphology translated to lath-like from M/A island. As a consequence, the ultimate tensile strength (UTS) and yield strength had a moderate increase from 1070 to 1110 MPa and 580 to 640 MPa, respectively. Meanwhile, the fracture elongation rose to the maximum 12.6% firstly and then decreased to about 9.0%. The optimizing mechanical properties with UTS up to 1090 MPa, yield ratio about 0.54 and fracture elongation about 13% could be obtained at the annealing temperature of 790°C for 120s.

Effect of Cooling Rate on the Microstructure and Mechanical Properties of Sn-0.7wt.%Cu Solder Alloy

2016 ◽  
Vol 675-676 ◽  
pp. 513-516 ◽  
Author(s):  
Phairote Sungkhaphaitoon ◽  
Thawatchai Plookphol
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Cooling Rate ◽  
Solder Alloy ◽  
Solder Alloys ◽  
Cooling Systems ◽  
Cooling Rates ◽  
Microstructure And Mechanical Properties ◽  
Two Phases

The dependence of microstructure and mechanical properties of Sn-0.7wt.%Cu solder alloys on different cooling rates were investigated. Two cooling rates were employed during solidification: 0.04 °C/s (mold-cooled system) and 1.66 °C/s (water-cooled system). The results showed that the ultimate tensile strength of Sn-0.7wt.%Cu solder alloy increased but the elongation decreased when water-cooled system was used. The microstructure of Sn-0.7wt.%Cu solder alloys solidified by both cooling systems exhibited two phases of Sn-rich and Cu6Sn5 intermetallic compounds (IMCs). However, finer grains were observed in the water-cooled specimens.

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