Fig. 1 a Specimen dimensions of the tensile test, b XRD patterns of recrystallized VCoNi alloys annealed at five different temperatures

Fig. 2 EBSD orientation maps of recrystallized VCoNi with different grain sizes: a d = 3.1 ± 0.4 μm, b d = 10.6 ± 1.3 μm, c d = 18.7 ± 2.3 μm, d d = 41.6 ± 2.5 μm, e d = 139.4 ± 11.9 μm

Fig. 3 Tensile engineering stress-engineering plastic strain curves of the VCoNi alloys with different grain sizes at the three testing temperatures: a 293 K, b 194 K, c 77 K, the inset in c shows a small stress drop after yielding for D3 alloys that was tested at 77 K. d Yield strength versus uniform elongation for VCoNi alloys at three different temperatures, AISI 304 at 77 K [36], AISI 316L at 110 K [37], AISI 321 at 110 K [37], AISI 347 at 110 K [37], 9% Ni steel at 77 K [38]

Fig. 4 Θ versus true plastic strain for the alloys with five different grain sizes deformed at 293 K a, 194 K b, 77 K c, the inset in a shows strain hardening rate recovery ∆Θ. Variation of initial strain hardening rate of stage II Θ0 and ∆Θ with grain size at three deformation temperatures: 293 K d, 194 K e, 77 K f

Fig. 5 Representative strain hardening curves of the alloys with different grain sizes deformed at 293 K and 77 K: a D3 alloys, b D42 alloys

Fig. 6 TEM bright-field micrographs with yellow dashed line of (111) slip trace and selected area diffraction patterns of the [011]-zone axis of uniform deformation area away from the fracture of D3 alloys and D42 alloys fractured at 293 K and 77 K: a D3 alloys at 293 K, b D3 alloys at 77 K, c D42 alloys at 293 K, d D42 alloys at 77 K

Fig. 7 TEM bright-field micrographs with yellow dashed line of (111) slip trace and selected area diffraction patterns of the [011]-zone axis of D42 alloys deformed at different true plastic strains at 293 K and 77 K: a 0.08 at 293 K, b 0.25 at 293 K, c 0.5 at 293 K, d 0.08 at 77 K, e 0.25 at 77 K, f 0.5 at 77 K

Fig. 8 TEM bright-field micrographs with yellow dashed line of (111) slip trace and selected area diffraction patterns of the [011]-zone axis of D3 alloys deformed at different true plastic strains at 293 K and 77 K: a 0.08 at 293 K, b 0.25 at 293 K, c 0.35 at 293 K, d 0.08 at 77 K, e 0.25 at 77 K, f 0.35 at 77 K

Fig. 9 Evolution of average slip band spacing of D3 alloys and D42 alloys deformed at 293 K and 77 K during tensile straining

Fig. 10 Recovery of strain hardening rate ∆Θ of alloys with different grain sizes at three different deformation temperatures