Effect of Grain Size on Mechanical Properties of Mg-0.3at.%Y Dilute Alloy

2018 ◽  
Vol 941 ◽  
pp. 790-795
Author(s):  
Rui Xiao Zheng ◽  
Ichiro Kawarada ◽  
Wu Gong ◽  
Akinobu Shibata ◽  
Hidetoshi Somekawa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
High Pressure Torsion ◽  
Tensile Elongation ◽  
Tensile Tests ◽  
Subsequent Annealing ◽  
High Yield ◽  
Grain Sizes ◽  
Mean Grain Size

In this study, a Mg-0.3at.%Y alloy was provided for a severe plastic deformation by high pressure torsion (HPT) and subsequent annealing. After the HPT by 5 rotations, nanocrystalline structures with a mean grain size of 0.23 μm having deformed characteristics were obtained. Fully recrystallized microstructures with mean grain sizes ranging from 0.66 μm to 32.7 μm were obtained by subsequent annealing at various temperatures. Room temperature tensile tests revealed that ultrafine grained (UFG; grain sizes smaller than 1 μm) specimen exhibited very high yield strength over 250 MPa but limited ductility. In contrast, good balance of strength and ductility was realized in fine grained specimens with grain sizes around 2~5 μm. Particularly, the yield strength and total tensile elongation of a specimen with a mean grain size of 2.13 μm were 184 MPa and 37.1%, respectively, which were much higher than those of pure Mg having a similar grain size. The significant effects of grain size and Y addition on the mechanical properties were discussed.

scholarly journals Tensile Strength and Creep Resistance in Nanocrystalline Cu, Pd and Ag

1990 ◽  
Vol 206 ◽  
Author(s):  
G. W. Nieman ◽  
J. R. Weertman ◽  
R. W. Siegel
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Yield Strength ◽  
Creep Resistance ◽  
Room Temperature ◽  
True Strain ◽  
Constant Load ◽  
Creep Tests ◽  
Grain Sizes

ABSTRACTMeasurements of tensile strength and creep resistance have been made on bulk samples of nanocrystalline Cu, Pd and Ag consolidated from powders by cold compaction. Samples of Cu-Cu2O have also been tested. Yield strength for samples with mean grain sizes of 5–80 nm and bulk densities on the order of 95% of theoretical density are increased 2–5 times over that measured in pure, annealed samples of the same composition with micrometer grain sizes. Ductility in the nanocrystalline Cu has exceeded 6% true strain, however, nanocrystalline Pd samples were much less ductile. Constant load creep tests performed at room temperature at stresses of >100 MPa indicate logarithmic creep. The mechanical properties results are interpreted to be due to grain size-related strengthening and processing flaw-related weakening.

Microstructure and Mechanical Properties of Extruded Mg-Al-Ca Based Alloys

2005 ◽  
Vol 488-489 ◽  
pp. 275-278 ◽  
Author(s):  
Rong Shi Chen ◽  
Jean Jacques Blandin ◽  
Michel Suéry ◽  
En Hou Han
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Elevated Temperature ◽  
Yield Strength ◽  
Ambient Temperature ◽  
Grain Refinement ◽  
Tensile Tests ◽  
Az91 Alloy ◽  
Microstructure And Mechanical Properties ◽  
Ca Addition

Mechanical properties and microstructure of extruded AZ91(-Ca) alloys have been studied in this paper. The results showed that Ca has no significant effect on reducing grain size of the extruded AZ91 alloy. The ambient temperature tensile tests showed that the ultimate and yield strength of extruded AZ91 alloy decreased by addition of Ca. At elevated temperature, Ca addition improves the yield strength of both AZ91 alloy. The variations in microstructure and mechanical properties of the AZ91 alloy are also discussed in terms of the effects of Ca on grain refinement and formation of constituent phases.

scholarly journals Achieving High Yield Strength and Ductility in As-Extruded Mg-0.5Sr Alloy by High Mn–Alloying

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4176
Author(s):  
Shibo Zhou ◽  
Xiongjiangchuan He ◽  
Peng Peng ◽  
Tingting Liu ◽  
Guangmin Sheng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
Tensile Yield Strength ◽  
High Yield ◽  
Compressive Yield Strength ◽  
High Yield Strength ◽  
Pinning Effect ◽  
Small Grains ◽  
Strength And Ductility

The effect of Mn on the microstructure and mechanical properties of as-extruded Mg-0.5Sr alloy were discussed in this work. The results showed that high Mn alloying (2 wt.%) could significantly improve the mechanical properties of the alloys, namely, the tensile and compressive yield strength. The grain size of as-extruded Mg-0.5Sr alloys significantly was refined from 2.78 μm to 1.15 μm due to the pinning effect by fine α-Mn precipitates during the extrusion. Moreover, it also showed that the tensile yield strength and the compressive yield strength of Mg-0.5Sr-2Mn alloy were 32 and 40 percent age higher than those of Mg-0.5Sr alloy, respectively. Moreover, the strain hardening behaviors of the Mg-0.5Sr-2Mn alloy were discussed, which proved that a large number of small grains and texture have an important role in improving mechanical properties.

Nanocrystalline Twinning Induced Plasticity Steel with Superior Mechanical Properties Fabricated by Cold Rolling and Annealing

2013 ◽  
Vol 753 ◽  
pp. 518-521
Author(s):  
Rajib Saha ◽  
Rintaro Ueji ◽  
Nobuhiro Tsuji
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
Tensile Ductility ◽  
Grain Boundary Character ◽  
Mean Grain Size ◽  
Cold Rolling And Annealing ◽  
Superior Mechanical Properties ◽  
Cold Rolled ◽  
Evolution Of Microstructure

A study has been carried out on the evolution of microstructure, grain boundary character and mechanical properties in a Twinning Induced Plasticity steel heavily cold rolled and subsequently annealed.The cold rolled mcrostructures showed fine lamellar boundaries with many shear bands.With progress of annealing, numerous numbers of recrystallized grains were generated.The fully recrystallized steel showed equi-axed nanocrystalline grains with a mean grain size of 400 nm that enhanced the yield strength significantly while retaining tensile ductility.

Microstructure and Mechanical Properties of Ultrafine-Grained Mg-Zn-Ca Alloy

2017 ◽  
Vol 381 ◽  
pp. 39-43 ◽  
Author(s):  
Olya B. Kulyasova ◽  
Rinat K. Islamgaliev ◽  
Ruslan Z. Valiev
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
High Pressure ◽  
Chemical Composition ◽  
High Pressure Torsion ◽  
Notable Effect ◽  
Ultrafine Grained ◽  
Mean Grain Size ◽  
High Microhardness ◽  
Mean Size

This paper studies the structure and mechanical properties of the Mg-1%Zn-xCa system subjected to high-pressure torsion (HPT) treatment. It was found that the chemical composition had a notable effect on the processes of grain refinement in the alloy. As is shown, HPT of Mg-1%Zn-0.005%Ca resulted in the formation of grains with a mean size of 250 nm, while HPT of the alloy with an increased content of Са up to 0.2% led to the formation of a nanostructure with a mean grain size of 90 nm. It is demonstrated that high microhardness is typical of all HPT-processed samples. The formation of fine Mg2Ca particles was established to increase the heat resistance of the alloy.

Dislocation study of ARMCO iron processed by ECAP

2016 ◽  
Vol 1818 ◽  
Author(s):  
Jairo Alberto Muñoz ◽  
Oscar Fabián Higuera ◽  
José María Cabrera
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Dislocation Density ◽  
Deformation Behavior ◽  
Armco Iron ◽  
Tensile Tests ◽  
Grain Sizes ◽  
Angular Pressing ◽  
Cylindrical Samples

ABSTRACTThe aim of this work was to study the deformation behavior of an Armco iron after severe plastic deformation by equal channel angular pressing (ECAP). Particular attention was paid to predict the dislocation density by different approaches like the model proposed by Bergström. Experimental measures of dislocation density by different techniques are used in the discussion. Cylindrical samples of ARMCO iron (8mm of diameter, 60mm of length) were subjected to ECAP deformation using a die with an intersecting channel of Φ=90° and outer arc of curvature of ψ= 37° die. Samples were deformed for up to 16 ECAP passes following route Bc. The mechanical properties of the material were measured after each pass by tensile tests. The original grain size of the annealed iron (70 μm) was drastically reduced after ECAP reaching grain sizes close to 300nm after 16 passes.

Submicron/nano Grained Stainless Steel with Superior Mechanical Properties

2005 ◽  
Vol 903 ◽  
Author(s):  
Shreyas Rajasekhara ◽  
M. C. Somani ◽  
M. Koljonen ◽  
L. P. Karjalainen ◽  
A. Kyröläinen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Austenitic Stainless Steels ◽  
Tensile Tests ◽  
Total Elongation ◽  
Fine Grained ◽  
Grain Sizes ◽  
Transmission Electron ◽  
Superior Mechanical Properties ◽  
Cold Rolled

AbstractMetastable austenitic stainless steels may transform to martensite when subjected to cold rolling. Upon subsequent annealing the martensite reverts back to ultra-fine grained austenite. Based on this concept, nano/submicron austenitic grains have been produced in a 63% cold rolled commercial AISI 301LN subjected to annealing treatments at 600°C, 800°C and 1000°C for 1, 10 and 100 seconds.Transmission Electron Microscopy (TEM) observations show the formation of equiaxed austenitic grains as small as ∼ 200nm in samples annealed at 800°C, and a dramatic increase in grain size as the annealing temperature and duration is increased. Additional tensile tests indicate that samples annealed at 800°C for 1 second exhibit a yield strength of ∼ 740 MPa and an total elongation of ∼ 45%. This combination of strength and ductility is excellent exceeding those of conventionally annealed steels (σy=350 MPa; Ductility ∼ 40%) or cold-rolled steels (σy=650 MPa; Ductility ∼ 30%).Finally, a correlation between the observed grain sizes and mechanical properties, in particular the yield strength, is obtained. Preliminary analysis indicates that the Hall-Petch equation can satisfactorily relate the observed yield strength with corresponding grain sizes.

Effects of W Addition on Microstructure and 650 °C Mechanical Properties of Ti-Al-Sn-Zr-Mo-Nb-W-Si Alloy

2021 ◽  
Vol 904 ◽  
pp. 53-58
Author(s):  
Wen Jing Zhang ◽  
Hao Feng Xie ◽  
Li Jun Peng ◽  
Zhen Yang ◽  
Guo Jie Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Temperature ◽  
Yield Strength ◽  
Stress Rupture ◽  
Tensile Tests ◽  
Optical Microscope ◽  
High Yield ◽  
Strengthening Effect ◽  
Α Phase

The influence of W addition on microstructure and mechanical properties of Ti-Al-Sn-Zr-Mo-Nb-W-Si high temperature titanium alloys are investigated by optical microscope (OM), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), tensile tests and large stress endurance tests at 650 °C. The results show that W is mainly solubilized in β phase. Microstructure observations indicate an obvious reduction in the size of transformed β structure (βt), primary α phase (αp) and the thickness of secondary lamellar α phase (αL), with the increase of W content. It is also observed that adding more W could improve the elongation, tensile strength and large stress rupture properties at 650 °C. However, combined with previous research, adding more β stabilizing elements could refine the size of each phase, which will be detrimental to the high temperature yield strength of the alloy. Therefore, in order to reasonably utilize the strengthening effect of W and make the alloy have high yield strength and tensile strength at 650 °C, its content should be controlled between 1 ~ 2 wt%

scholarly journals Grain Size Effect on the Mechanical Behavior of Metastable Fe-23Cr-8.5Ni Alloy

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 734 ◽  
Author(s):  
Lin Xie ◽  
Chunpeng Wang ◽  
Yuhui Wang ◽  
Guilin Wu ◽  
Xiaoxu Huang
Keyword(s):  
Grain Size ◽  
Yield Strength ◽  
Size Effect ◽  
Mechanical Behavior ◽  
Tensile Elongation ◽  
Model Material ◽  
Coarse Grained ◽  
High Yield ◽  
Grain Size Effect ◽  
Structural Refinement

An Fe-23Cr-8.5Ni alloy was used as a model material to study the grain size effect on the mechanical behavior of metastable duplex metal. Alloy samples with different grain sizes ranging from 0.1 to 2 μm were prepared by cold-rolling and annealing. A structural refinement to about 0.1 μm results in a high yield strength but very limited ductility. A significant improvement of ductility occurred at the grain size of about 0.4 μm. A further increase in grain size results in a decreased strength and a slightly improved ductility. The alloy with a grain size of about 0.4 μm exhibits an excellent combination of strength and ductility, where the yield strength and tensile elongation are increased up to 738 MPa and 29% as compared to 320 MPa and 33% of a coarse-grained (about 2 μm) sample, respectively. The origin of the excellent mechanical properties was attributed to the unique deformation characteristics associated with the transformation induced plasticity and the development of back stress.

Microstructure Development and Ductility of Ultra-Fine Grained Mg-Gd Alloy Prepared by High Pressure Torsion

2009 ◽  
Vol 633-634 ◽  
pp. 353-363 ◽  
Author(s):  
Jakub Čížek ◽  
Ivan Procházka ◽  
Bohumil Smola ◽  
Ivana Stulíková ◽  
Vladivoj Očenášek ◽  
...  
Keyword(s):  
Grain Size ◽  
High Pressure ◽  
Elevated Temperatures ◽  
High Pressure Torsion ◽  
High Sensitivity ◽  
Tensile Tests ◽  
Lattice Defects ◽  
Coarse Grained ◽  
Fine Grained ◽  
Mean Grain Size

Microstructure of ultra fine grained (UFG) Mg-Gd alloy prepared by high-pressure torsion (HPT) was investigated in the present work. Lattice defects introduced by HPT were characterized at first. Subsequently thermal stability of UFG structure and its development with annealing temperature were studied and correlated with changes of hardness and ductility. Precipitation effects in the alloy with UFG structure were compared with those in a conventional coarse-grained alloy. Defect studies were performed by positron annihilation spectroscopy (PAS), which represents well established non-destructive technique with a high sensitivity to open volume lattice defects like vacancies, dislocations, misfit defects etc. PAS investigations were combined with transmission electron microscopy (TEM) and X-ray diffraction (XRD). Changes of mechanical properties were monitored by Vicker’s microhardness (HV) and deformation tensile tests. It was found that HPT deformed Mg-Gd alloy exhibits UFG structure with mean grain size of 100 nm and a dense network of dislocations distributed uniformly throughout the whole sample. Although recovery of dislocations takes place at relatively low temperatures, it is not accompanied by grain growth and the mean grain size remains around 100 nm up to 300oC. Tensile tests performed at elevated temperatures to examine ductility showed that HPT-deformed alloy exhibits a superplastic behavior at 400oC. Moreover, it was found that the precipitation sequence in HPT-deformed alloy differs from that in conventional coarse-grained material.

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