Temperature Dependence of Mechanical Properties and Plastic Flow Behavior of Cast Multicomponent Alloys Fe20Cr20Mn20Ni20Co20-xCx (x = 0, 1, 3, 5)

Abstract

The paper presents the experimental data on the temperature dependence of mechanical properties and plastic flow behavior of cast alloys Fe 20 Cr 20 Mn 20 Ni 20 Co 20-x C x (x = 0, 1, 3, 5) in the temperature range from 77 to 297 K. In the as-cast state, high-entropy Cantor alloy Fe 20 Cr 20 Mn 20 Ni 20 Co 20 and multicomponent alloy Fe 20 Cr 20 Mn 20 Ni 20 Co 19 C 1 have an austenitic structure, while carbon doping results in solid solution strengthening of austenitic grains and carbide precipitation at the grain boundaries. The temperature dependence of the yield stress for the Fe 20 Cr 20 Mn 20 Ni 20 Co 19 C 1 alloy significantly exceeds the σ 0.2 (T) dependence for the Fe 20 Cr 20 Mn 20 Ni 20 Co 20 alloy. Carbon-assisted solid solution strengthening is accompanied by an increase in flow stress and strain hardening as well as by a decrease in low-temperature plasticity in the

Temperature-Dependent Deformation Behavior of “γ-austenite/δ-ferrite” Composite Obtained through Electron Beam Additive Manufacturing with Austenitic Stainless-Steel Wire

“…As a result, δ-ferrite can assist the activation of dislocation sources in a primary slip system and those with non-maximum Schmid factors (secondary slip systems), enhance the multiple slip and promote the accumulation of dislocations in the interdendritic austenite. We confirmed the similar effects using transmission electron microscopical studies of a high-nitrogen steel and the multicomponent alloys with the coarse "hard" particles [29,32]. The stress-assisted multiple slip promotes high strain hardening in stage I for the AM and the AM + SST samples as compared to single-phase as-cast material (Figures 2 and 3).…”

“…This difference is compensated by the δ-ferrite-assisted change in the local stress state in a bulk of the materials. Due to the different elastic properties of the austenite and ferrite, the "hard" δ-ferrite lamellae play the role of stress concentrators under external loading [26][27][28][29] and can initiate a macroplastic flow at stresses, which are lower than the YS γ+δ calculated using the "rule of mixtures". This question is still open and needs a precise calculation of the YS in the framework of a separate paper.…”

Effect of carbon alloying on hydrogen embrittlement of a Cantor alloy

“…Doping with carbon leads to a significant increase in the strength properties of the initial specimens (without hydrogen-charging). This is caused by solid-solution strengthening and grain refinement, as it was previously reported for multicomponent alloys with interstitial atoms in [3,11,13]. Carbon-alloying in accompanied with the decrease in elongation-to-failure of Cantor alloy.…”

“…Besides, the limitation of the fcc HEAs as an engineering material due to the low yield strength [4,5] stimulates the research of interstitially-alloyed HEAs, in particular, the carbon-alloyed Cantor alloy. Due to the solid-solution strengthening and precipitation hardening, the addition of carbon increases the strength of fcc HEAs without a significant loss of ductility [11][12][13]. Up to date, there are insufficient data on the effect of interstitial atoms on the hydrogen embrittlement of HEAs, and they are controversial.…”