the effect of carbon content of the mechanical properties - McMaster ...

M.A.Sc. Thesis – E. E. Yang McMaster – Materials Science & Engineering
The local stresses in austenite and ε-martensite were also examined as a function
of the global strain as seen in Figure 6.9. The ε-martensite local stress was above the
austenite phase indicating the ε-martensite was loaded more heavily. The difference
between the model and the two phases was seen to be less at low levels of strain and
increased slightly with strain before reaching constant proportions.
Figure 6.9 Iso-Work Model Local Stress – Global Strain of 0.2C Alloy
Global strain in the 0.2C alloy and the local strains in the two phases from
Equation 6.6 were also plotted in Figure 6.10 to show the relative contributions of each
phase to strain partitioning. Both austenite and ε-martensite were strained equally at low
strains before austenite began contributing more to the global strain. This indicated the
austenite as a softer phase compared to the ε-martensite and the difference was seen to
increase with global strain.
local/global stress
1400
1200
1000
800
600
400
200
0.2C alloy
Austenite
martensite
0
0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40
global strain
116