8/19/2019 Modes of Solidification

1/13

8/19/2019 Modes of Solidification

2/13

Case Study

Objective: Infuence o cooling rate on themicrostructure o stainless steel alloys and theconditions that lead to many microstructural

morphologies that develop during solidication.

Experimental Details:

Material: Fe - Ni – Cr alloy used.

Specific Parameters:

  EB urace !la"ing  #-$% &o%er 'evel  (ravel peed- )- *+++ mm,s

8/19/2019 Modes of Solidification

3/13

8/19/2019 Modes of Solidification

4/13

8/19/2019 Modes of Solidification

5/13

Cooling-Rate Calculations

• Relationships between the DAS and the cooling rate (! have

 been developed"

8/19/2019 Modes of Solidification

6/13

Contd

• #he res$lts show that the primar% DAS decreases from a val$e

of &' µm to "&) *m for the highest travel speed"

• #he primar% DAS res$lts predict a cooling+rate variation of

more than six orders of magnit$de, from - ./s to -"0 1234 ./s

for the highest speed melt"

8/19/2019 Modes of Solidification

7/13

Ma!!ing t"e PSM as a Function o# Cooling Rate

and Co$!osition

• #he seven allo%s containing 05 6 7e and var%ing 8r/9i ratios

were cast and s$rface melted at six different travel speeds"

• #hese specimens were anal%ed b% optical microscop% to

determine the primar% mode of solidification"

• Some of the s$rface melts showed more than one mode of

solidification thro$gho$t the cross section"

• ;n these cases, the mode that was responsible for more than

06 of the microstr$ct$re was considered to be the dominant

mode"

8/19/2019 Modes of Solidification

8/13

8/19/2019 Modes of Solidification

9/13

8/19/2019 Modes of Solidification

10/13

Conclusions

;n s$mmar%, 0 modes of solidification and 2' morphologieswere observed d$ring the resolidification of the high+p$rit%

7e+9i+8r allo%s"

#he morphological feat$res were shown to be related to the

allo% composition, the cooling rate, and the extent of the

solid+state transformation of ferrite"

8/19/2019 Modes of Solidification

11/13

8ontd=

#he development of each of the 2' solidification

microstr$ct$res is listed in #able >;;"

#his s$mmar% is believed to represent the complete ?set? of

 possible solidification and solid+state transformation events

that occ$r d$ring the resolidification of SS# allo%s"

8/19/2019 Modes of Solidification

12/13

Re#e%ences

2icrostructural development during solidication ostainless steel alloys.

 3elding 2etallurgy y indo 4ou.

 . 4atayama and 5. 2atsuna%a6 Proc. ICALEO,0178 pp. )+-)9.

 .5. :avid8 ;.2.

8/19/2019 Modes of Solidification

13/13

T"an& you'''