  This work demonstrates the development of a strong and ductile medium entropy
alloy by employing conventional alloying and thermomechanical processing to
induce partial recrystallization (PR) and precipitation strengthening in the
microstructure. The combined usage of electron microscopy and atom probe
tomography reveals the sequence of microstructural evolution during the
process. First, the cold working of homogenized alloy resulted in a highly
deformed microstructure. On annealing at 700{\deg}C, B2 ordered precipitates
heterogeneously nucleate on the highly misoriented sites. These B2 promotes
particle stimulated nucleation (PSN) of new recrystallized strain-free grains.
The migration of recrystallized grain boundaries leads to discontinuous
precipitation of L12 ordered regions in highly dense lamellae structures.
Atomic-scale compositional analysis reveals a significant amount of Ni confined
to the GB regions between B2 and L12 precipitates, indicating Ni as a
rate-controlling element for coarsening the microstructure. On 20 hours of
annealing, the alloy comprises a composite microstructure of soft
recrystallized and hard non-recrystallized zones, B2 particles at the grain
boundaries (GBs), and coherent L12 precipitates inside the grains. The B2 pins
the GB movement during recrystallization while the latter provides high
strength. The microstructure results in a 0.2% yield stress (YS) value of 1030
MPa with 32% elongation at ambient temperature and retains up to 910 MPa at
670{\deg}C. Also, it shows exceptional microstructural stability at 700 {\deg}C
and resistance to deformation at high temperatures up to 770{\deg}C.
Examination of deformed microstructure reveals excessive twinning, formation of
stacking faults, shearing of L12 precipitates, and accumulation of dislocations
at around the B2 precipitates and GBs attributed to high strain hardening of
the alloy.
