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| Constitutive Model and Microstructural Evolution of TRIP-Assisted
Duplex Stainless Steel Under High Strain Rate Compressive Loading |
| LI, Xiao-Long, GUO, Shu |
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Cite this article:
LI, Xiao-Long, GUO, Shu. Constitutive Model and Microstructural Evolution of TRIP-Assisted
Duplex Stainless Steel Under High Strain Rate Compressive Loading. Acta Metall Sin, 0, (): 0-.
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Abstract Mn-N-alloyed
transformation-induced plasticity (TRIP)-assisted duplex stainless steel is a
promising Ni-saving advanced high-strength steel for impact-resistant
structural applications due to its high strength, good plasticity, and the TRIP
effect. However, under high-strain-rate compression, adiabatic temperature rise
can enhance austenite stability, suppress martensitic transformation, and
render conventional dynamic constitutive descriptions insufficient. This
work investigates a Mn-N-alloyed TRIP-assisted duplex stainless steel through
quasi-static compression and split Hopkinson pressure bar tests across a wide
strain-rate range, from 2.0 × 10−3 s−1 to 4.0 × 103 s−1. Specimens were compressed along the rolling direction. The
strain-rate-dependent mechanical response was analyzed alongside the evolution
of martensite fraction, phase transformation behavior, local misorientation,
crystallographic texture, and deformation substructures. SEM, EBSD, TEM,
magnetic measurements, and thermodynamic calculations of the stacking fault
energy were combined to reveal the underlying deformation mechanisms. Based on
these findings, a modified Johnson–Cook constitutive model incorporating
adiabatic heating was established to describe the steel’s dynamic flow
behavior. Results show that the duplex stainless steel exhibits an excellent
combination of high strength and plasticity, with no shear fracture observed
during high-strain-rate impact compression. Both dynamic yield strength and
compressive strength increase with increasing strain rate. At a strain rate of
4.0 × 103 s−1, the yield strength and compressive
strength along the rolling direction reach 800 and 1143 MPa, respectively. The
deformation mechanism changes substantially with strain rate. Under
quasi-static compression, significant martensitic transformation occurs via
both γ→ε→α¢ and γ→α¢ transformation paths, and
the volume fraction of α′ martensite reaches 8.66%. By contrast, at 4.0 × 103 s−1, adiabatic heating enhances austenite stability and suppresses
the TRIP effect, reducing the α′ martensite fraction to 0.92%. The
transformation path is then dominated by the direct γ→α¢ transformation, whereas the γ→ε→α¢ route is strongly
inhibited. Thermodynamic calculations show that the stacking fault energy
increases from 20.92 mJ/m2 at room temperature to 41.08 mJ/m2 under the highest-strain-rate condition. This shifts the deformation mode from
TRIP-dominated deformation toward a synergistic mechanism involving deformation
twinning, the residual TRIP effect, and dislocation slip. TEM observations
further confirm that plastic deformation at high strain rates is primarily
facilitated by the formation of dislocation walls in ferrite, along with
dislocation slip, stacking faults, and deformation twins in austenite. The
modified Johnson–Cook model, which introduces adiabatic temperature rise into
the thermal softening term, accurately reproduces the nonlinear dynamic flow
stress response while avoiding the overestimation associated with the
conventional isothermal Johnson–Cook model. These findings provide a
mechanistic basis and a constitutive description for the application of
TRIP-assisted duplex stainless steels in impact-resistant structural design.
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Received: 07 November 2025
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| Fund: National Natural Science Foundation of China(No.52275388); National Natural Science Foundation of China(No.52375388); Natural Science Foundation of Hebei Province(No.E2022203206); Hebei Provincial Department of Education Universities Science and Technology Research Project (Science and Engineering)-Young Scientists Fund(No.QN2025125); Shijiazhuang's University-Industry-Academia Cooperation Project in Hebei Province-Major Science and Technology Special Project(No.241080457A); Cultivation Project for Basic Research and Innovation of Yanshan University(No.2022BZZD002); Central Guiding Local Science and Technology Development Fund Projects(No.236Z1008G); Central Guiding Local Science and Technology Development Fund Projects(No.236Z1016G); Natural Science Foundation of Hebei Province-Chunhui Talents Program(No.A2023203021); Central Guiding Local Science and Technology Development Fund Projects(No.246Z1016G) |
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