scholarly journals Grain Size Effect of the γ Phase Precipitation on Martensitic Transformation and Mechanical Properties of Ni–Mn–Sn–Fe Heusler Alloys

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2339
Author(s):  
Jinpei Guo ◽  
Minting Zhong ◽  
Wei Zhou ◽  
Yajiu Zhang ◽  
Zhigang Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Martensitic Transformation ◽  
Annealing Time ◽  
Volume Fraction ◽  
Heusler Alloys ◽  
Coarse Grained ◽  
Dual Phase ◽  
Average Grain Size ◽  
Stress Hysteresis

Isothermal annealing of a eutectic dual phase Ni–Mn–Sn–Fe alloy was carried out to encourage grain growth and investigate the effects of grain size of the γ phase on the martensitic transformation behaviour and mechanical properties of the alloy. It is found that with the increase of the annealing time, the grain size and volume fraction of the γ phase both increased with the annealing time predominantly by the inter-diffusion of Fe and Sn elements between the γ phase and the Heusler matrix. The isothermal anneals resulted in the decrease of the e/a ratio and suppression of the martensitic transformation of the matrix phase. The fine γ phase microstructure with an average grain size of 0.31 μm showed higher fracture strength and ductility values by 28% and 77% compared to the coarse-grained counterpart with an average grain size of 3.31 μm. The fine dual phase microstructure shows a quasi-linear superelasticity of 4.2% and very small stress hysteresis during cyclic loading, while the coarse dual phase counterpart presents degraded superelasticity of 2.6% and large stress hysteresis. These findings indicate that grain size refinement of the γ phase is an effective approach in improving the mechanical and transformation properties of dual phase Heusler alloys.

scholarly journals Enhanced Mechanical Properties of Mg-6Sn-3Al-1Zn Alloy with Bimodal Grain Size Disturbed in the Microstructure Uniformly through Changing the Rolling Temperature

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Fuan Wei ◽  
Jinhui Wang ◽  
Ping Li ◽  
Bo Shi
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
Volume Fraction ◽  
Rolling Temperature ◽  
Average Grain Size ◽  
Small Grains ◽  
Mg2sn Phase ◽  
Average Size ◽  
Bimodal Grain Size

The mechanical properties of Mg-6Sn-3Al-1Zn alloy were enhanced with bimodal grain size disturbed in the microstructure uniformly; the Mg-6Sn-3Al-1Zn alloys were rolled with 60% thickness reduction at different rolling temperatures. The results have shown that the Mg-6Sn-3Al-1Zn alloys are composed of Mg2Sn phase and α-Mg matrix phase. When the rolling temperature was less than or equal to 400°C, with the rolling temperature increasing, the average size and volume fraction of Mg2Sn phase and the average grain size of small grains remained unchanged, the average grain size of large grains decreased, the volume fraction of small grains increased, and the yield strength of the alloy increased. When the rolling temperature reached 450°C, the average size and volume fraction of Mg2Sn phase and the average grain size of large grains increased, and the volume fraction of small grains and the yield strength of the alloy decreased. The elongation increased with the rolling temperature increasing, but the change trend of hardness was just opposite. When the alloy was rolled at 400°C, the average sizes of small grains, large grains, and Mg2Sn phases were 3.66 μm, 9.24 μm, and 19.5 μm, respectively. The volume fractions of small grains, large grains, and Mg2Sn phases were 18.6%, 77.6%, and 3.8%, respectively. And the tensile properties reached the optimum; for example, the tensile strength, yield strength, elongation, and Vickers hardness were 361 MPa, 289.5 MPa, 20.5%, and 76.3 HV, respectively.

Influence of Grain Size on Mechanical Properties in a Fe-9Ni-12Mn-2.5Si-1.0C TWIP Steel

2011 ◽  
Vol 197-198 ◽  
pp. 655-661
Author(s):  
Ze Bin Yang ◽  
Ding Yi Zhu ◽  
Wei Fa Yi ◽  
Shu Mei Lin ◽  
Cheng Mei Du
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Strain Hardening ◽  
Twip Steel ◽  
Optical Microscope ◽  
Coarse Grained ◽  
Microstructure Observation ◽  
Transmission Electron ◽  
Average Grain Size

We investigate the influence of grain size on mechanical properties in a Fe-9Ni-12Mn-2.5Si-1.0C TWIP steel by unidirectional tensile. Meanwhile the microstructures of the TWIP steel were observed and analyzed by optical microscope (OM) and transmission electron microscope (TEM). The experimental results show that the TWIP steel’s yield strength and tensile strength decrease with the increasing of grain size, whereas the plasticity increases with it. When the average grain size reaches to 27μm, the tensile strength is 1080MPa, the elongation percentage is 77%, and the strength-plasticity product achieves the 83160MPa•%. Steel’s strain hardening rate can be changed from three-stage to four-stage with the increasing of grain sizes, the areas of strain hardening by twin deformation mechanism are expanded. Through the microstructure observation we found that, coarse-grained TWIP steel conducts to twinning formation, the high density twins can increase the alloy’s ductility by splitting the grain.

Effect of Grain Size on Mechanical Properties of Dual Phase Steels Composed of Ferrite and Martensite

MRS Advances ◽  
2016 ◽  
Vol 1 (12) ◽  
pp. 811-816 ◽  
Author(s):  
Myeong-heom Park ◽  
Akinobu Shibata ◽  
Nobuhiro Tsuji
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Tensile Test ◽  
Coarse Grained ◽  
Dual Phase ◽  
Fine Grained ◽  
Grain Sizes ◽  
Dp Structure ◽  
Dp Steels

ABSTRACTIt is well-known that dual phase (DP) steels composed of ferrite and martensite have good ductility and plasticity as well as high strength. Due to their excellent mechanical properties, DP steels are widely used in the industrial field. The mechanical properties of DP steels strongly depend on several factors such as fraction, distribution and grain size of each phase. In this study, the grain size effect on mechanical properties of DP steels was investigated. In order to obtain DP structures with different grain sizes, intercritical heat treatment in ferrite + austenite two-phase region was carried out for ferrite-pearlite structures having coarse and fine ferrite grain sizes. These ferrite-pearlite structures with coarse and fine grains were fabricated by two types of heat treatments; austenitizing heat treatment and repetitive heat treatment. Ferrite grain sizes of the specimens heat-treated by austenitizing and repetitive heat treatment were 47.5 µm (coarse grain) and 4.5 µm (fine grain), respectively. The ferrite grain sizes in the final DP structures fabricated from the coarse-grained and fine-grained ferrite-pearlite structures were 58.3 µm and 4.1µm, respectively. The mechanical behavior of the DP structures with different grain sizes was evaluated by an uniaxial tensile test at room temperature. The local strain distribution in the specimens during tensile test was obtained by a digital image correlation (DIC) technique. Results of the tensile test showed that the fine-grained DP structure had higher strength and larger elongation than the coarse-grained DP structure. It was found by the DIC analysis that the fine-grained DP structure showed homogeneous deformation compared with the coarse-grained DP structure.

scholarly journals Further Research on Hardenability of Ti-1023 β Alloy Leading to a New DOE

2020 ◽  
Vol 321 ◽  
pp. 12032
Author(s):  
Bohumil Prazak
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Martensitic Transformation ◽  
Volume Fraction ◽  
Nucleation Mechanism ◽  
Alpha Particles ◽  
Primary Alpha ◽  
Trade Off ◽  
Nucleation Mechanisms

As part of a treatise on the hardenability of Ti-1023, a summary about the nucleation mechanisms of primary and secondary alpha, the viability of two-step aging, and existence of precipitation-free zones is provided. Assumptions are given on the nucleation mechanism of primary alpha particles and the effect of higher beta stabiliser content on stress-induced martensitic transformation. It is reminded that further research into two-step aging would be beneficial. A proposed design of the experiment deals with the existence of martensite in stressed samples, so that the martensitic transformation is minimized by an increased content of beta stabilisers, volume fraction of primary alpha, and beta grain size. Finally, a microstructure with stress-induced omega particles as precursors of secondary alpha particles may result in a better trade-off of mechanical properties; it is suggested that this be explored.

Dual-phase nanocrystalline Ni–Co alloy with high strength and enhanced ductility

2010 ◽  
Vol 25 (2) ◽  
pp. 401-405 ◽  
Author(s):  
Liyuan Qin ◽  
Jianshe Lian ◽  
Zhonghao Jiang ◽  
Guoyong Wang ◽  
Qing Jiang
Keyword(s):  
Grain Size ◽  
Room Temperature ◽  
High Strength ◽  
High Rate ◽  
Coarse Grained ◽  
Dual Phase ◽  
Ductile Materials ◽  
Average Grain Size ◽  
Elongation To Failure ◽  
Critical Scale

A dual-phase (DP) Ni–66.7%Co alloy with an average grain size of 16 nm was fabricated by electrodeposition. It exhibited an ultimate tensile strength of 1800–2080 MPa, together with an elongation to failure of 10–15% at room temperature. The remarkable ductility of this DP alloy with critical scale grains was attributed to its sustained high rate of strain hardening. Its fracture surface showed an unexpected deeply dimpled structure similar to that of coarse-grained ductile materials, which also witnesses the improved ductility.

Microstructures, Mechanical Properties and Textures of Deep Drawing Dual-Phase Steel

2012 ◽  
Vol 535-537 ◽  
pp. 670-673
Author(s):  
Jie Yun Ye ◽  
Zheng Zhi Zhao ◽  
Zhi Gang Wang ◽  
Ai Min Zhao ◽  
Jing Jing Chen
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Dual Phase Steel ◽  
Tensile Tests ◽  
Rolled Sheet ◽  
Dual Phase ◽  
Annealing Texture ◽  
Average Grain Size ◽  
R Value ◽  
Heterogeneous Deformation

C-Mn-Cr-Mo dual phase steel was piloted in laboratory. OM, SEM, tensile tests and XRD were used to characterize the microstructures, mechanical properties and to determine the texture. The results indicate that when annealed at 860 °C, the tensile strength of the tested steel is 440 MPa, elongation and r value exceed 35% and 1.4, respectively. With the temperature increases from 820°C to 860°C, the average grain size of ferrite increases and ferrite trends to be uniform gradually, therefore, the r value increase gradually. When the temperature is higher than 860°C, bainite forming results in reducing of r value. Al could weaken the tendency of heterogeneous deformation and modified the annealing texture by refining hot-rolling grain size. Mo-based carbides existed in hot-rolled sheet developed {111} texture in the stage of ferrite recrystallization, then re-dissolved in intercritial annealing stage so as to improve hardenability.

Influence of Asymmetric Rolling on the Deformation Textures, Grain Size and Mechanical Properties of B4C/Al Composite

2016 ◽  
Vol 851 ◽  
pp. 196-200
Author(s):  
Bing Feng Li ◽  
Qiu Lin Li ◽  
Wei Liu ◽  
Zhen Hong Wang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Volume Fraction ◽  
Small Diameter ◽  
Diameter Ratio ◽  
Asymmetric Rolling ◽  
Al Composite ◽  
Average Grain Size ◽  
Cold Rolling And Annealing ◽  
Deformation Textures

B4C/Al composite was a promising neutron absorb material. In this work, B4C/Al composite sheets were asymmetrically rolled and annealed. The asymmetric (ASR) condition was introduced by applying mismatched roll diameters with diameter ratios of 1.1, 1.2 and 1.3, respectively., while the symmetric rolling (SR) was used as the control experiment. Mechanical properties and microstructures of the composite were tested after cold rolling and annealing. Results showed that: ASR with small diameter ratio decreased the texture volume fraction in the B4C/Al composite, but when diameter ratio of ASR reached 1.3 new slip systems were actuated and the texture volume fraction started to increase. The average grain size of the aluminium matrix was smaller after ASR, and it decreased with the increasing diameter ratio. The hardness of B4C/Al composite after ASR was about 40% higher than the one rolled by symmetric rolling, proved that ASR is a promising way to enhance the properties of B4C/Al composite.

Microstructure Evolution and Mechanical Properties of Titanium Nickelide during Pressing in Equal-Channel Angular Matrix with Quasi-Small Angle of Channels Intersection

2021 ◽  
Vol 410 ◽  
pp. 123-127
Author(s):  
Abdrakhman B. Naizabekov ◽  
Dmitry V. Kuis ◽  
Andrey V. Kasperovich
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Microstructure Evolution ◽  
Small Angle ◽  
Titanium Nickelide ◽  
Coarse Grained ◽  
Ultrafine Grained Structure ◽  
Ultrafine Grained ◽  
Average Grain Size

The article presents the results of the analysis of the microstructure and mechanical properties of titanium nickelide formed during pressing in an equal-channel angular matrix with a quasi-small angle of channels intersection. The conducted studies have shown that pressing in an equal-channel angular matrix with a quasi-small angle of channels intersection ensures the formation of a homogeneous sub-ultrafine-grained structure in the titanium nickelide alloy, while the average grain size, decreasing by 100-200 times, is 0.3-0.5 microns, and the tensile strength increases to 1350 MPa in 6 passes, which is almost 90% higher than in the coarse-grained quenched state.

Microstructure Evolution and Mechanical Behavior in Shape Memory Nanostructured TiNi Alloy

2018 ◽  
Vol 385 ◽  
pp. 169-174 ◽  
Author(s):  
Anna Misochenko ◽  
Jeevanandham Vijaya Tilak Kumar ◽  
Sudha Jayaprakasam ◽  
K. Anantha Padmanabhan ◽  
Vladimir Stolyarov
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Microstructure Evolution ◽  
Mechanical Response ◽  
Coarse Grained ◽  
Tini Alloy ◽  
Nanostructured Alloys

Influence of grain size on the martensitic transformation and mechanical properties of shape memory alloy Тi49.3Ni50.7 was studied. The features of the mechanical response of coarse-grained and nanostructured alloys were identified. The microstructure investigations involved the use of TEM and SEM.

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