November 2020 Volume 2

FORGING RESEARCH AND TECHNOLOGY

FORGING RESEARCH

FORGING RESEARCH

FORGING RESEARCH

3.6.4 Continuous Cooling Condition after Deformation Three cooling rates were selected after deformation: 1°C/min, 20°C/min and 100°C/min. The same process was conducted for all samples studied. In addition, the EBSD-IQ and IPF analyses were performed in order to understand the microstructural phase balance in the samples. Figure 38 and Figure 39 show this analysis for all the samples studied at this stage. KAM is high in deformed grains due to higher dislocation density and stored energy. So, as expected, the deformed sample has a higher local grain misorientation value, represented n blue (0.507 to 0.485 for the SLM un-deformed sample and 0.484 to 0.299 for the wrought un-deformed sa le). 3.6.4. Continuous Cooling Condition after Deformation Three cooling rates were selected after deformation: 1°C/min, 20°C/ in and 100°C/min. The same process was conducted for all samples studied. In addition, the EBSD-IQ nd IPF analyses were performed in order to understand the microstructural phase balance in the samples. Figure 38 and Figure 39 show this analysis for all the samples studied at this stage

Figure 36: KAM map for the SLM 4340 (A) WQ prior to deformation, and (B) WQ after deformation. ( B ) Figure 36: KAM map for the SLM 4340 ( A ) WQ prior to deformation, and ( B ) WQ after deformation. ( A ) ( B ) Figure 36: KAM map for the SLM 4340 ( A ) WQ prior to deformation, and ( B ) WQ after deformation. ( A )

( A )

( B )

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( C )

( D )

Figure 37: KAMmap for the wrought 4340 (A) WQ prior to deformation, and (B) WQ after deformation. KAM is high in deformed grains due to higher dislocation density and stored energy. So, as expected, the deformed sample has a higher local grain misorientation value, represented in blue (0.507 to 0.485 for the SLM un-deformed sample and 0.484 to 0.299 for the wrought un-deformed sample). ( B ) Figure 37: KAM map for the wrought 4340 ( A ) WQ prior to deformation, and ( B ) WQ after deformation. ( A ) ( B ) Figure 37: KAM map for the wrought 4340 ( A ) WQ prior to deformation, and ( B ) WQ after deformation. ( A )

30

31

30

( E )

( F )

111

101

001

Figure 38: Inverse Pole Figure (IPF), and grayscale IQ-map and grain boundary distribution, for the SLM 4340 cooled at (A, B) 1C/min, (C, D) 20C/min and (E, F) 100C/min; after deformation. Figure 38: Inverse Pole Figure (IPF), and grayscale IQ-map and grain boundary distribution, for the SLM 4340 cooled at ( A, B ) 1C/min, ( C, D ) 20C/min and ( E, F ) 100C/min; after deformation.

0 0.1 0.2 0.3 0.4 0.5

MA – 14.2% Pearlite – 23.3% Ferrite – 62.5%

Frequency

0 20 40 60 80 100

IQ

( A )

0.3

MA – 3.5% Martensite – 25.7% Granular Bainite – 34.5% Bainite – 36.6%

0.2

0.1

FIA MAGAZINE | NOVEMBER 2020 97

0

Frequency

0 20 40 60 80 100

IQ

( B )