A facile strengthening method by co-doping boron and nitrogen in CoCrFeMnNi high-entropy alloy

Strategies for Achieving Strength–Ductility Synergy in Face‐Centered Cubic High‐ and Medium‐Entropy Alloys

“…Besides, H, O, and Si have also been used for interstitial strengthening in some HEAs/MEAs, such as doping H into the Co 20 Cr 20 Fe 20 Mn 20 Ni 20 HEA, [108] O into the ZrTiHfNb 0.5 Ta 0.5 [109] and TiZrHfNb [110] HEAs, Si into the CoCrFeNi, [111] Co 0.2 CrAlNi, [112] and FeCoCrNiMn [113] HEAs, and multiple interstitials (containing at least two elements of B, C, N, and O) into certain HEAs. [114,115] Here, it should be pointed out that different from the dilatational stress field that have little interaction with screw dislocations caused by the addition of substitutional solutes, interstitial solutes generally cause a tetragonal distortion to the lattice, producing a shear field that strongly interacts with the edge, screw, and mixed dislocations. [74] Therefore, the interstitial strengthening is usually stronger than the substitutional strengthening in terms of strengthening effect.…”

“…The other strengthening mechanisms in the HEAs including GB strengthening, precipitation strengthening, and dislocation strengthening are similar to those in the conventional metals and alloys, and thus classical models can be used to evaluate reasonably the strength gains in HEAs/MEAs. More importantly, these traditional strengthening strategies based on the simple introduction of dislocation barriers inevitably limit the proliferation and accumulation of dislocations, which would lead to a decline in the ductility, [36,50,86,114,145,148,149,155,159,[181][182][183][184][185][186][187][188][189][190][191][192][193][194][195] as shown in Figure 8. Therefore, in the exploration of simultaneous enhancement of strength and ductility in FCC HEAs/MEAs, the efforts of materials scientists have never stopped.…”

“…Following this idea, several strategies have been proposed with some success, some of which are discussed below. [36,50,86,114,145,148,149,156,159,[181][182][183][184][185][186][187][188][189][190][191][192][193][194][195] Here, Δε and Δσ represent the increase in uniform elongation and ultimate tensile strength caused by strengthening, respectively.…”

“…Besides, H, O, and Si have also been used for interstitial strengthening in some HEAs/MEAs, such as doping H into the Co 20 Cr 20 Fe 20 Mn 20 Ni 20 HEA, [ 108 ] O into the ZrTiHfNb 0.5 Ta 0.5 [ 109 ] and TiZrHfNb [ 110 ] HEAs, Si into the CoCrFeNi, [ 111 ] Co 0.2 CrAlNi, [ 112 ] and FeCoCrNiMn [ 113 ] HEAs, and multiple interstitials (containing at least two elements of B, C, N, and O) into certain HEAs. [ 114,115 ]…”

“…Figure 8. Strength-ductility trade-off caused by traditional strengthening strategies for FCC HEAs/MEAs, grouped by strengthening mechanisms [36,50,86,114,145,148,149,156,159,[181][182][183][184][185][186][187][188][189][190][191][192][193][194][195]. Here, Δε and Δσ represent the increase in uniform elongation and ultimate tensile strength caused by strengthening, respectively.…”