scholarly journals Microstructure Evolution and Tensile Properties of 304L Stainless Steel Subjected to Surface Mechanical Attrition Treatment

2010 ◽  
Vol 667-669 ◽  
pp. 175-179 ◽  
Author(s):  
Ping Jiang ◽  
Jian Lu ◽  
Xiao Lei Wu
Keyword(s):  
Mechanical Property ◽  
Stainless Steel ◽  
Uniform Elongation ◽  
Tensile Tests ◽  
Bulk Sample ◽  
Coarse Grained ◽  
Surface Mechanical Attrition Treatment ◽  
Uniaxial Tensile ◽  
304L Stainless Steel ◽  
Mechanical Attrition

A gradient nanostructured layer (GNsL) was generated on the two sides of bulk sample in 304L stainless steel by means of the surface mechanical attrition treatment. The microstructure of the GNsL was characterized via TEM observation. The prominent microstructural features involve the intersection of multi-system twin operation, subdividing the original grains into blocks, a martensite transformation mainly occurring at the interface of the twins as well, and the randomly orientated nanocrystallites at the top of surface. After annealing at 750°C for 10 min, recovery had occurred and the dislocation density was much reduced. The vast majority of the grains at the top surface were in the nanocrystalline/ultrafine range, with some recrystallization regions. The uniaxial tensile tests were performed to obtain the mechanical property of bulk samples with GNsL. The yield strength was about 2 times higher than that of the coarse-grained counterpart, but with a decrease in uniform elongation and elongation to failure as well. The relationship between the microstructure and mechanical property was discussed in detail.

scholarly journals Microstructure and Mechanical Properties of 316L Stainless Steel Fabricated Using Selective Laser Melting

MRS Advances ◽  
2019 ◽  
Vol 4 (44-45) ◽  
pp. 2431-2439
Author(s):  
N. Iqbal ◽  
E. Jimenez-Melero ◽  
U. Ankalkhope ◽  
J. Lawrence
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Selective Laser Melting ◽  
Laser Scanning ◽  
316L Stainless Steel ◽  
Uniform Elongation ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Laser Melting ◽  
Sample Height

ABSTRACTThe microstructure homogeneity and variability in mechanical properties of 316L stainless steel components fabricated using selective laser melting (SLM) have been investigated. The crack free, 99.9% dense samples were made starting from SS316L alloy powder, and the melt pool morphology was analysed using optical and scanning electron microscopy. Extremely fast cooling rates after laser melting/solidification process, accompanied by slow diffusion of alloying elements, produced characteristic microstructures with colonies of cellular substructure inside grains, grown along the direction of the principal thermal gradient during laser scanning. In some areas of the microstructure, a significant number of precipitates were observed inside grains and at grain boundaries. Micro hardness measurements along the build direction revealed slight but gradual increase in hardness along the sample height. Uniaxial tensile tests of as manufactured samples showed the effect of un-melted areas causing scatter in room-temperature mechanical properties of samples extracted from the same SLM build. The ultimate tensile strength (UTS) varied from 458MPa to 509MPa along with a variation in uniform elongation from 3.3% to 14.4%. The UTS of a sample exposed to the Cl- rich corrosion environment at 46oC temperature revealed a similar strength as of the original sample, indicating good corrosion resistance of SLM samples under those corrosion conditions.

scholarly journals Mechanical Property of Duplex Stainless Steel with Nanostructured Layer by Surface Mechanical Attrition Treatment

2011 ◽  
Vol 682 ◽  
pp. 123-130 ◽  
Author(s):  
Liu Chen ◽  
Xiao Lei Xu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Property ◽  
Stainless Steel ◽  
Tensile Test ◽  
Duplex Stainless Steel ◽  
Electron Backscatter Diffraction ◽  
Annealed Sample ◽  
Surface Mechanical Attrition Treatment ◽  
Mechanical Attrition ◽  
Deformed Layer

A grain size gradient layer material was produced by means of surface mechanical attrition treatment on a UNS S32304 duplex stainless steel. In this study, the mechanical property was characterized by tensile test, while microstructure was investigated by transmission electron microscopy, scanning electron microscopy and electron backscatter diffraction. The deformed layer enhanced both the yield strength and maximum strength with large ductility retained, as revealed by tensile test that the yield stress of 30 minutes processed sample was 702 MPa as compared with 454 MPa of as-annealed sample. The elongation to failure, however, decreased from 0.41 to 0.27.

scholarly journals Mechanical Properties and Microstructure of a Duplex Nanostructure

2010 ◽  
Vol 667-669 ◽  
pp. 973-978
Author(s):  
L. Chen ◽  
Ping Jiang ◽  
Xiao Lei Wu ◽  
Mu Xin Yang ◽  
Chang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Yield Strength ◽  
Uniform Elongation ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Uniaxial Tensile ◽  
Plastic Behavior ◽  
Angular Pressing ◽  
Elongation To Failure

The nanostructure was obtained in a duplex stainless steel (DSS) by means of equal channel angular pressing. The mechanical properties were characterized by uniaxial tensile tests, while the microstructure was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was shown that the yield strength in a deformed nanostructure increased significantly from 402 MPa to 1461 MPa as compared to its coarse-grained counterpart. In contrast, the uniform elongation decreased significant to only 2% together with elongation to failure of 9.8%, much lower than those of 25.4% and 42.6%. After annealing at 700°C for 10 minute, however, uniform elongation increases to 5.3% with the yield strength of 1200 MPa. TEM observation exhibited that deformation twins prevail in the austenite phase whereas the dislocations of high density present in ferrite. The plastic behavior in both phases was analyzed based on the deformation twinning and the presence of dislocation. Finally, the effect of the microstructure on mechanical properties was discussed.

scholarly journals Microstructure Evolution and Mechanical Properties of Austenite Stainless Steel with Gradient Twinned Structure by Surface Mechanical Attrition Treatment

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1624
Author(s):  
Aiying Chen ◽  
Chen Wang ◽  
Jungan Jiang ◽  
Haihui Ruan ◽  
Jian Lu
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Surface Mechanical Attrition Treatment ◽  
Spatial Distributions ◽  
Gradient Structure ◽  
Mechanical Attrition ◽  
Gradient Microstructure ◽  
Strength And Plasticity

Gradient structures in engineering materials produce an impressive synergy of strength and plasticity, thereafter, have recently attracted extensive attention in the material families. Gradient structured stainless steels (SS) were prepared by surface mechanical attrition treatment (SMAT) with different impacting velocities. The microstructures of the treated samples are characterized by gradient twin fraction and phase constituents. Quantitative relations of gradient microstructure with impacting time and mechanical properties are analyzed according to the observations of SEM, TEM, XRD, and tests of mechanical property. The processed SSs exhibited to be simultaneously stiff, strong, and ductile, which can be attributed to the co-operation of the different spatial distributions of multi-scaled structures. The formation of gradient twinned structure is resolved and the strengthening by gradient structure is explored.

Effect of Strain Rate on the Deformation-Induced Martensite Transformation and Mechanical Behavior of Austenitic Stainless Steels for Cold Stretched Pressure Vessels

2010 ◽  
Author(s):  
Cunjian Miao ◽  
Yaxian Li ◽  
Jinyang Zheng
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Martensite Transformation ◽  
Magnetic Measurement ◽  
Austenitic Stainless Steels ◽  
Tensile Tests ◽  
Pressure Vessels ◽  
Uniaxial Tensile ◽  
Work Hardening Rate ◽  
Proof Strength

Cold stretching (pressure strenghtening) technique has been widely used in austenitic stainless steel pressure vessels in order to increase the proof strength and lighten the weight of the vessels. Cold stretching technique is performed by applying the strengthening pressure under a specified strain rate. Plastic deformation in the process will lead to martensite transformation and may influence material’s strength and ductility. Cold stretching tests of EN 1.4301 stainless steel are carried out at different quasi-static strain rates of 10−3 and 10−5/s, following the uniaxial tensile tests at the same strain rate of 2.5×10−3/s. The α′-martensite transformation is detected by magnetic measurement, meanwhile the work-hardening rate, the flow stress and the mechanical properties of material are studied and the results are presented.

Strain Hardening Modeling of High-Strength Stainless Steel Tube

2011 ◽  
Vol 311-313 ◽  
pp. 2014-2019
Author(s):  
Ruo Dong Lu ◽  
He Yang ◽  
Heng Li ◽  
Ze Kang Wang ◽  
Mei Zhan ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Strain Hardening ◽  
Large Strain ◽  
High Strength ◽  
Tensile Tests ◽  
Steel Tube ◽  
Uniaxial Tensile ◽  
Stainless Steel Tube ◽  
Hardening Models ◽  
Piecewise Functions

By the uniaxial tensile tests of both the arc and tube section samples, the strain hardening curves of 21-6-9 high-strength stainless steel tube(HSST) are obtained. Considering that the uniform plastic deformation stage of the curve is short and the flow stress in large strain area is unknown for this tube, different strain hardening models have been established based on single and piecewise functions, respectively. By comparing the experimental results and the numerical ones in terms of load-displacement curves, it shows the constitutive model achieved by three Swift fitting functions can better characterize the strain hardening response of the 21-6-9 HSST in large strain region.

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