modes of solidification
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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 #-$% &o%er 'evel (ravel peed- )- *+++ mm,s
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Cooling-Rate Calculations
• Relationships between the DAS and the cooling rate (! have
been developed"
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Contd
• #he res$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$de, from - ./s to -"0 1234 ./s
for the highest speed melt"
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Ma!!ing t"e PSM as a Function o# Cooling Rate
and Co$!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"
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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"
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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"
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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.
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T"an& you'''
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