Analysis of Precipitates: M 2 N M 2 N precipitates in a 16%Cr - - PowerPoint PPT Presentation

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Analysis of Precipitates: M 2 N M 2 N precipitates in a 16%Cr - - PowerPoint PPT Presentation

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Analysis of Precipitates: AlN, M 23 C 6 020 000 001 000 220 011 200 010 M 23 C 6 , [001] Z.A. AlN , [100] Z.A. 0.5 m 0.5 m 110 Hot rolled strip of Fe 16Cr 0.5Mn 0.1Ni 0.1Al 0.07C 0.03N 000 100 (mass-%)

slide-1
SLIDE 1
  • J. Mola, I. Jung, J. Park, D. Chae, B.C. De Cooman, Ridging Control in Transformable Ferritic Stainless Steels, Metall. Mater. Trans. A. 43 (2012) 228–244.

AlN , [001] Z.A. 000 110 010 100

0.5 μm

000 020 220 200 M23C6 , [001] Z.A.

0.5 μm

AlN , [100] Z.A. 000 001 011 010

0.5 μm

Analysis of Precipitates: AlN, M23C6

AlN: 𝑄63𝑛𝑑, a=0.311 nm, c=0.498 nm M23C6: Fmത 3𝑛, a=1.05 nm Hot rolled strip of Fe16Cr0.5Mn0.1Ni0.1Al0.07C0.03N (mass-%) ferritic stainless steel BF, SAD

slide-2
SLIDE 2

2 1 / n m 2 1 / n m

113 ZA of M23C6 113 ZA of M23C6 422 422 220 422 422 220

311 ZA of M23C6 311 ZA of M23C6

2-4-2 2-2-4 0-22 2-4-2 2-2-4 02-2

Twinned M23C6 precipitates in a 16%Cr ferritic stainless steel

  • J. Mola, Ridging Resistance and Formability in the AISI 430 Transformable Ferritic Stainless Steel, doctoral dissertation, POSTECH, South Korea, 2012.

Analysis of Precipitates: Twinned M23C6

BF, DF, SAD

slide-3
SLIDE 3

AlN AlN

  • J. Mola, I. Jung, J. Park, D. Chae, B.C. De Cooman, Ridging Control in Transformable Ferritic Stainless Steels, Metall. Mater. Trans. A. 43 (2012) 228–244.

STEM images and EDS analysis of AlN and M23C6 precipitates in a hot rolled strip

  • f

Fe16Cr0.5Mn0.1Ni0.1Al 0.07C0.03N (mass-%) ferritic stainless steel

M23C6

Analysis of Precipitates: AlN, M23C6

STEM, EDS

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SLIDE 4

axis : [3,5,-1]

35-1 Z.A. of bcc // 112 Z.A. of hcp

1-1-2 bcc 3-2-1 bcc 2-11 bcc

  • 10-3 bcc

Orientation Relationship (110)bcc // (001)hcp <111>bcc // <110>hcp

  • J. Mola, Ridging Resistance and Formability in the AISI 430 Transformable Ferritic Stainless Steel, doctoral dissertation, POSTECH, South Korea, 2012.

Analysis of Precipitates: M2N

M2N precipitates in a 16%Cr ferritic stainless steel

M2N: 𝑄63/𝑛𝑛𝑑, a=0.274 nm, c=0.444 nm BF, SAD

slide-5
SLIDE 5

Orientation Relationship (110)bcc // (001)hcp <111>bcc // <110>hcp

  • J. Mola, Ridging Resistance and Formability in the AISI 430 Transformable Ferritic Stainless Steel, doctoral dissertation, POSTECH, South Korea, 2012.
  • 11-1 hcp
  • 01-1 hcp
  • 100 hcp
  • 1-10 bcc

110 bcc

Elongated M2N precipitates in a 16%Cr ferritic stainless steel

Analysis of Precipitates: M2N

BF, SAD

slide-6
SLIDE 6
  • R. Rahimi, B.C. De Cooman, H. Biermann, J. Mola, Microstructure and mechanical properties of Al-alloyed Fe–Cr–Ni–Mn–C stainless steels, Mater. Sci. Eng. A. 618

(2014) 46–55. doi:10.1016/j.msea.2014.09.001.

Faulted M7C3 carbides in an Fe17Cr6Mn3Ni4Al0.45C duplex stainless steel

Analysis of Precipitates: M7C3

BF, SAD

Faulted

slide-7
SLIDE 7
  • Q. Huang, B.C. De Cooman, H. Biermann, J. Mola, Influence of

Martensite Fraction on the Stabilization of Austenite in Austenitic–Martensitic Stainless Steels, Metall. Mater. Trans. A. 47 (2016) 1947–1959.

  • J. Mola, B.C. De Cooman, Quenching and Partitioning (Q&P)

Processing of Martensitic Stainless Steels, Metall. Mater. Trans. A. 44 (2013) 946–967.

Analysis of Precipitates: M3C

BF DF1 DF2 Dark field imaging of a tempered Fe13Cr0.3C martensitic stainless steel using two different cementite reflections

BF, DF, SAD

  • 200
  • 2-401

2402 011

  • 2201
  • 2202
  • 2001

2002 0-201 0202

  

Z.A.: [0-11]//[001]1//[001]2

Orthorhombic M3C (): a= 0.509 nm b= 0.674 nm c= 0.452 nm

Bagaryatski O.R.: {112} // {010} <01-1> // <001>

SAD pattern of martensite and two cementite (θ) variants

0.5 m

slide-8
SLIDE 8

0.3 μm

A B

  • R. Rahimi, P. Pekker, H. Biermann, O. Volkova, B.C. De Cooman, J. Mola, Volumetric changes associated with B2-(Ni,Fe)Al dissolution in an Al-alloyed ferritic steel, Mater. Des.

111 (2016) 640–645. doi:10.1016/j.matdes.2016.09.033.

011 111 100 B2 0ത 11 Z.A. Ferrite 0ത 11 Z.A.

(A) (B)

011 200 211 B2-(Ni,Fe)Al intermetallics exhibiting a cube-on-cube O.R. with the ferritic matrix Fe17Cr6Mn9Ni7Al0.46C ferritic stainless steel

Only weak B2 reflections

Analysis of Precipitates: B2

BF, SAD

slide-9
SLIDE 9

a)

c) SAD pattern of c) 111 002 113 222 004

e)

Analysis of Precipitates: VN

  • M. Wendler, B. Reichel, R. Eckner, O. Fabrichnaya, L. Krüger, A. Weiß, J. Mola, Effect of Vanadium Nitride Precipitation on Martensitic Transformation and Mechanical

Properties of CrMnNi Cast Austenitic Steels, Metall. Mater. Trans. A. 47 (2016) 139–151.

20 nm 30 nm SAD pattern of (c)

VN precipitates in an Fe15Cr6Mn3Ni0.65V0.5Si 0.11C0.24N austenitic stainless steel

HRTEM, SAD

slide-10
SLIDE 10

0.4 µm

Recrystallization / Precipitation

TEM montage of ferrite and Cr carbides and nitrides in an Fe16Cr0.4Mn0.1Ni0.04C0.04N ferritic stainless steel Annealing time: 30 s + 30 s

  • J. Mola, E. Seo, I. Jung, B.C.De Cooman, J. Park, Cold rolling of α+ α′ dual-phase microstructure in transformable ferritic stainless steel, in: Proceedings of 7th Eur.
  • Stainl. Steel Conf. Sci. Mark., Como, Italy, 2011.

BF

slide-11
SLIDE 11
  • J. Mola, E. Seo, I. Jung, B.C.De Cooman, J. Park, Cold rolling of α+ α′ dual-phase microstructure in transformable ferritic stainless steel, in: Proceedings of 7th Eur.
  • Stainl. Steel Conf. Sci. Mark., Como, Italy, 2011.

1 µm

TEM montage of ferrite and Cr carbides and nitrides in an Fe16Cr0.4Mn0.1Ni0.04C0.04N ferritic stainless steel Annealing time: 30 min

Recrystallization / Precipitation

BF

slide-12
SLIDE 12

Recrystallization of Martensite and Ferrite

  • J. Mola, B.C. De Cooman, J. Park, Recrystallization behavior of α′ martensite in transformable ferritic stainless steels, in: Proceedings of 7th Eur. Stainl. Steel Conf. Sci. Mark.,

Como, Italy, 2011.

0.5 µm

(a)

0.5 µm

  • Rex. 

Recovered 

(d) (e)

0.2 µm

  In-lath precipitates Twin boundary precipitates Twin boundary precipitates

Difference in the recrystallization behavior of ferrite and martensite in a cold-rolled Fe16Cr0.4Mn0.1Ni0.04C0.04N ferritic-martensitic stainless steel BF DF

α αʹ

Annealing conditions: rapid heating to 750 °C and immediate cooling BF, DF

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SLIDE 13

Bulging Recrystallization of  Due to the high density of lath boundary precipitates, bulging of recrystallized regions into recovered martensite preferentially occurs in the longitudinal directions of laths.

Recrystallization of Martensite

  • J. Mola, B.C. De Cooman, J. Park, Recrystallization behavior of α′ martensite in transformable ferritic

stainless steels, in: Proceedings of 7th Eur. Stainl. Steel Conf. Sci. Mark., Como, Italy, 2011.

Fe16Cr0.4Mn0.1Ni0.04C0.04N dual-phase stainless steel

  • Rex. annealing conditions:

15 s 830 °C BF

slide-14
SLIDE 14

1 µm

  • J. Mola, B.C. De Cooman, J. Park, Recrystallization behavior of α′ martensite in transformable ferritic stainless steels, in: Proceedings of 7th Eur. Stainl. Steel Conf. Sci. Mark.,

Como, Italy, 2011.

Bulging Recrystallization of  Due to the high density of lath boundary precipitates, bulging of recrystallized regions into recovered martensite preferentially occurs in the longitudinal directions of laths.

Recrystallization of Martensite

Fe16Cr0.4Mn0.1Ni0.04C0.04N dual-phase stainless steel

  • Rex. annealing conditions:

15 s 830 °C BF

slide-15
SLIDE 15

Twin boundary

002 tw

  • 111 tw
  • 111
  • 111 tw
  • 11-1

00-2 000

1 µm

Stacking Faults

bcc bcc bcc 

Stabilization of austenite in an Fe16Cr0.4Mn0.1Ni0.04C0.04N transformable stainless steel obtained by Q&P processing

  • J. Mola, B.C. De Cooman, Quenching and partitioning processing of transformable ferritic stainless steels, Scr. Mater. 65 (2011) 834–837.

BF

slide-16
SLIDE 16

BF DF1, ε+α DF2, ε DF3, α 0.1 m

  • J. Mola, M. Wendler, A. Weiß, B. Reichel, G. Wolf, B.C. De Cooman, Segregation-Induced Enhancement of Low-Temperature Tensile Ductility in a Cast High-Nitrogen

Austenitic Stainless Steel Exhibiting Deformation-Induced α′ Martensite Formation, Metall. Mater. Trans. A. 46 (2015) 1450–1454.

Deformation-Induced Martensite

Z.A. γ ത ത ε α 3 ത ത ത ത 3 ത ത

BF DF1 DF2 DF3

αʹ-martensite formation at intersections of ε-martensite plates in Fe14.3Cr5.5Mn5.5Ni0.5Si0.37N0.02C austenitic stainless steel

BF, DF, SAD εV2 εV1

slide-17
SLIDE 17

B.C. De Cooman, P. Gibbs, S. Lee, D.K. Matlock, Transmission Electron Microscopy Analysis of Yielding in Ultrafine-Grained Medium Mn Transformation-Induced Plasticity Steel, Metall. Mater. Trans. A. 44 (2013) 2563–2572.

Deformation-Induced Martensite

1 2

2 1/ nm 2 1/ nm 2 1/ nm 2 1/ nm

Region 1: γ+ε Region 2: γ+αʹ+ε Strain-induced γ ε  αʹ transformation route in an Fe7Mn0.1C medium Mn steel

BF, SAD

slide-18
SLIDE 18

α α  

Fe− Cr− Mo−0. C−0.4N

0.2 µm

Fe− Cr− Mo−0. C−0.4N stainless steel after partial transformation to spontaneous (athermal) α-martensite

Spontaneous Martensite

  • J. Mola, Considerations in the design of formable austenitic stainless steels based on deformation-induced processes, in Austenitic Stainless Steels - New Aspects, Eds. W.

Borek, T. Tański, Z. Brytan, InTechOpen, Typesetting stage.

BF

slide-19
SLIDE 19

Fe− Cr− Mo−0. C−0.4N steel after partial transformation to spontaneous (athermal) α-martensite

α  α 

0.2 µm Densely-packed stacking faults

112 Z.A.

11ത 1 3ത 1ത 1 2ത 20 O

0.2 µm

 

Planar faults Small specimen tilt

  • Q. Huang, B.C.De Cooman, H. Biermann, J. Mola, Influence of Martensite Fraction on the Stabilization of Austenite in Austenitic–Martensitic Stainless Steels, Metall. Mater.
  • Trans. A. 47 (2016) 1947–1959.

111 planes

Spontaneous Martensite

BF, SAD

slide-20
SLIDE 20

50 nm 50 nm

Analysis of Precipitates: B2 and σ-Phase

5 1/ nm 5 1/ nm

Ferrite + B2-NiAl

BF DF using the marked B2/σ common spot BF DF, B2 precipitates SAED, encircled area

201α Z.A. // 201B2 Z.A. // 23-6σ Z.A.

  • 1-12α,B2
  • 112α,B2

020α,B2

  • 102B2

301σ 010B2 3-20σ 021σ

σ-phase: tetragonal P42/mnm, a=0.880 nm, c=0.4544 nm

Unpublished

Fe17Cr6Mn 3Ni4Al0.45C duplex stainless steel BF, DF, SAD

100 nm 100 nm