Improved ductility by coupled motion of grain boundaries in nanocrystalline B2-FeCo alloys

Molecular dynamics study on the deformation and fracture of FeCo-based alloys

“…This situation compels the microstructure to adapt through grain rotation and grain boundary sliding. This expectation is consistent with the results obtained from atomistic simulations conducted by Li et al [47], where FeCo shows an extended plastic deformation. However, the authors observed crack formation at ~9% strain but without observing fracture below 30% strain.…”

“…Unlike other MD studies on FeCo [47,121], the present simulations show that the stresses are not exclusively accommodated in the GBs. In the case of the binary FeCo and the alloys containing V and Mo, multiple slip bands emerge, promoting strain hardening until reaching the ultimate tensile strength (UTS).…”

“…Nonetheless, as the authors claim this potential was tuned specifically for HEA study, it was not tuned for other alloys, including the binary interaction in discussion. Li et al [47] focused their research on the FeCo alloy and improved the EAM interatomic potential developed by Zhou et al [32,33] to examine its mechanical properties. In their study, they went beyond considering just the basic properties of the B2 structure and incorporated the APB energies for the common FeCo slip planes in their fitting procedure, namely {110} and {112}.…”

“…However, given the low vacancy concentration in metals, especially at nanoscale, the predicted error is acceptable. 141 120-160 [10] 129 [11], 126 [38] 128 [37], 127 [47] 𝛾 𝐴𝑃𝐵 (112) 176 169 [11], 157 [38] 159 [37], 140 [47] 𝐸 𝐹𝑒 𝛽 0.14 0.7 [32], 0.17 [11] 𝐸 𝐶𝑜 𝛼 0.23 0.7 [32], 0.17 [11] 𝐸 𝑣 𝛼 with bcc-Fe and hcp-Co as reference states.…”

“…Nevertheless, the structural and elastic properties of the B2 structure are predicted as described by the original potential [52]. [80], 263 [81], 195 [38] 232 [121], 226 [49] , 231 [47] C12 206 154 [80], 152 [81], 137 [38] 167 [121], 168 [49] , 179 [47] C44 150 130 [80], 108 [81], 123 [38] 144 [121], 136 [49] , 138 [47] B 217 165 [79] 189 [80,81], 196 [32] 189 [121], 196 [47] ΔH -10.93 -8.30 [16], -12.51 [77] -11.04 [121], -9.79 [49], -11.61 [16] 𝛾 𝐴𝑃𝐵 (110) 131 120-160 [10,227] 129 [11], 126 [39], 126 [38] 141 [121], 128 [37], 127 [47] 𝛾 𝐴𝑃𝐵 (112) 151 169 [11], 168 [39], 157 [38] 176 [121], 159 [37], 140 [47] 𝐸 𝐹𝑒 𝛽 0.14 0...…”