Prakt. Met. Sonderband 38 (2006) 39 
e to Bucher ALLOY 0.05A1-550 ALLOY 1%AI-550 
d for these TIA=750 C, 60s, 15C/sec to 450C, Quench TIA=770 C, 60s, 15C/sec to 450C, Quench 
f DP steels, . ma 
ly observed ma oul ine 
y to easily | am i en 
lled ferrite i esteem en 
al, and new Y 
rrite would or 
oS 
BDP-790 
Austenite (Martensite) = 26.55% Austenite (Martensite) = 16.38% 
Recrystallized Ferrite= 37.17% Recrystallized Ferrite= 50.97% 
Non-RXD + New Ferrite= 36.28% Non-RXD + New Ferrite= 29.13% 
New Ferrite = 36.28-27.78= 8.5% New Ferrite = 29.13-16.9= 12.23% 
Retained Austenite= 0% Retained Austenite=3.52% 
Figure 10: IQ multi-peak quantitative analysis of TRIP steels varying Al content. 
{ 
SD T,»=770 C, 60s, Quench 1,,=860 C, 60s, Quench 
rss i Re = or Se i GB Contribution 
ygonal F 0.16 == Non-RXD Ferrite pe a 
-Polygonal F = Martensite 6 Sum of all simulated contributions 
tensite 014 —- Sum of all simulated contributions 
g 012 ‘i 
g 01 
$ 0.08 
0.06 
0.04 
0.02 
OR a vei Ann 
aring TRIP > 10 20 30 40 50 o 60 70 80 90 100 Ar - N © so “ 7 N i 
[19] The © 
05 to 1.0%. Austenite (Martensite) = 30.2% Austenite (Martensite) = 57.5% 
rature, Ha Recrystallized Ferrite= 52.8% Recrystallized Ferrite= 32.4% 
Gi wi th Non-recrystallized Ferrite= 16.9% Non-recrystallized Ferrite= 10.1% 
Normalized RXD Ferrite = 75.7% Normalized RXD Ferrite = 76.2% 
checked by 
i) annealed Figure 11: IQ multi-peak quantitative analysis of 1.0Al TRIP steel. 
us times at 
The influence of intercritical annealing temperature on the microstructure found after cooling to 450°C 
at 15°C/sec and WQRT with no holding time at 450°C is shown in Figure 11 for the steel containing 
el is shown 1.0Al. As expected, the higher annealing temperature resulted in a lower carbon content in the 
eels after a intercrically formed austenite and subsequently lower hardenability. The amount of new ferrite formed 
hing to RT. upon cooling was about 44% with the 860°C anneal, but only 12% for 770°C. Annealing at 860°C 
| appears to would also be expected to lead to more austenite being formed. Hence, the sum of the new ferrite plus 
of a higher the martensite was 57% for the 860 anneal but only about 22% for the 770°C anneal, even taking the 
much more retained austenite into account. The formation of the austenite appeared to occur at the expense of some 
of the recrystallized ferrite in the specimens annealed at 860°C. Normally, it would be expected that