Structural changes in metastable austenitic steel during equal channel angular pressing and subsequent cyclic deformation

Добаткин, С. В.; Skrotzki, Werner; Rybalchenko, O. V.; Терентьев, В. Ф.; Belyakov, Andrey; Prosvirnin, D. V.; Рааб, Г. И.; Zolotarev, E. V.

doi:10.1016/j.msea.2018.03.018

Cited by 25 publications

(10 citation statements)

References 34 publications

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“…Regarding ASSs, due to the absence of a notable phase transformation during the thermal treatment, grain refinement has been achieved by static recrystallization (SRX), dynamic recrystallization (DRX), formation and reversion of strain‐induced martensite, and various severe plastic deformation techniques . In fact, many commercial ASSs are metastable against the martensitic transformation during deformation.…”

Section: Introductionmentioning

confidence: 99%

Effects of Grain Size on Mechanical Properties and Work‐Hardening Behavior of AISI 304 Austenitic Stainless Steel

Naghizadeh

Mirzadeh

2019

steel research int.

120

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Grain size effects on the properties of AISI 304 austenitic stainless steel are studied. Yield stress (YS) and ultimate tensile strength (UTS) increased with decreasing grain size (Hall–Petch law) while the difference between YS and UTS decreased. Three distinct stages for work‐hardening rate are identified: I) initial rapid fall until reaching a minimum value, II) subsequent rise to a maximum due to the transformation‐induced plasticity (TRIP) effect, which is found to enhance by increasing grain size, and III) final fall until the onset of necking. More in‐depth analysis on the mechanical stability of austenite reveals that for below‐average grain size of ≈50 μm, by decreasing grain size, the TRIP effect diminishes; whereas for grain size larger than ≈50 μm, by increasing grain size, the TRIP effect becomes less pronounced. Due to the strong TRIP effect, high incremental work‐hardening exponents (n‐values of higher than 0.8) and low‐yield ratios (smaller than 0.5) are observed. It is also found that when the average grain size increases, the tensile toughness and the size and depth of dimples increase. The latter is responsible for the tardiness of the microcavity coalescence, which is indicative of high ductility of this austenitic alloy.

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Section: Introductionmentioning

confidence: 99%

Effects of Grain Size on Mechanical Properties and Work‐Hardening Behavior of AISI 304 Austenitic Stainless Steel

Naghizadeh

Mirzadeh

2019

steel research int.

120

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“…These targets can be achieved by severe plastic deformation (SPD) [15], equal channel angular pressing (ECAP) [16] being a particularly promising method. Thus, it is known that in addition to enhancing strength of metallic materials [17,18,19], ECAP may also lead to improvement of their in-service properties, such as corrosion resistance [20,21], fatigue life [18,22], wear resistance [23], electrical conductivity [24] and so forth. Improving the strength and in-service properties becomes possible due to the formation of the ultrafine-grained (UFG) structure and a profuse system of grain boundaries in the materials.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Equal-Channel Angular Pressing on the Microstructure, the Mechanical and Corrosion Properties and the Anti-Tumor Activity of Magnesium Alloyed with Silver

et al. 2019

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The effect of equal-channel angular pressing (ECAP) on the microstructure, texture, mechanical properties, corrosion resistance and cytotoxicity of two magnesium-silver alloys, Mg-2.0%Ag and Mg-4.0%Ag, was studied. Their average grain size was found to be reduced to 3.2 ± 1.4 μm and 2.8 ± 1.3 μm, respectively. Despite the substantial grain refinement, a drop in the strength characteristics of the alloys was observed, which can be attributed to the formation of inclined basal texture. On a positive side, an increase in tensile ductility to ~34% for Mg-2.0%Ag and ~27% for Mg-4.0%Ag was observed. This effect can be associated with the activity of basal and prismatic slip induced by ECAP. One of the ECAP regimes tested gave rise to a drop in the corrosion resistance of both alloys. An interesting observation was a cytotoxic effect both alloys had on tumor cells in vitro. This effect was accompanied with the release of lactate dehydrogenase, an increase in oxidative stress, coupled with the induction of NO-ions and an increase in the content of such markers of apoptosis as Annexin V and Caspase 3/7. Differences in the chemical composition and the processing history-dependent microstructure of the alloys did not have any significant effect on the magnitude of their antiproliferative effect.

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“…The fatigue ratio σ f / σ UTS as an indicator of the working capacity after ECAP is only slightly reduced for 316L steel and even increased for Cr–Ni–Ti steel. This can be explained by the fact that the additional strain hardening of Cr–Ni–Ti steel is associated with not only the rearrangement of the dislocation substructure, but also with the formation of deformation induced martensite in the local metal zones (Dobatkin et al, ).…”

Section: Resultsmentioning

confidence: 99%

The influence of ultrafine‐grained structure on the mechanical properties and biocompatibility of austenitic stainless steels

et al. 2019

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In this study, equal‐channel angular pressing (ECAP) of austenitic 316L and Cr–Ni–Ti stainless steels was carried out. Effect of ECAP at 400°C on the evolution of the microstructure, mechanical properties, and biocompatibility of these steels was investigated. The biocompatibility of samples with the ultrafine grain structure obtained in the ECAP process did not deteriorate in comparison with an austenitic 316L stainless steel in coarse‐grained state. However, this treatment enhances the multipotent mesenchymal stromal/stem cell proliferation by 26% for 316L steel and by 17% for Cr–Ni–Ti stainless steel in comparison with coarse‐grained counterparts. At the same time, ECAP contributes to a significant improvement in performance and weight reduction of medical devices, which is especially important for the creation of implanted prostheses for replacement of skeletal defects, due to significant increase in specific strength of steels. The strength properties of austenitic stainless steels were remarkably improved due to the grain refinement and deformation twinning resulted from ECAP at 400°C. After ECAP, the yield strength of 316L and Cr–Ni–Ti stainless steels increased by 4.2 and 2.9 times up to 950 and 900 MPa, and the fatigue limit by 2 and 1.7 times up to 500 and 475 MPa, respectively, comparing to coarse‐grained counterparts.

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Structural changes in metastable austenitic steel during equal channel angular pressing and subsequent cyclic deformation

Cited by 25 publications

References 34 publications

Effects of Grain Size on Mechanical Properties and Work‐Hardening Behavior of AISI 304 Austenitic Stainless Steel

Effects of Grain Size on Mechanical Properties and Work‐Hardening Behavior of AISI 304 Austenitic Stainless Steel

The Effect of Equal-Channel Angular Pressing on the Microstructure, the Mechanical and Corrosion Properties and the Anti-Tumor Activity of Magnesium Alloyed with Silver

The influence of ultrafine‐grained structure on the mechanical properties and biocompatibility of austenitic stainless steels

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