Metastability-assisted fatigue behavior in a friction stir processed dual-phase high entropy alloy

Abstract

Metastability-based high entropy alloy design opens a new strategic path for designing highstrength materials. However, high strength is always coupled with poor damage tolerance under cyclic loading conditions (fatigue). To overcome this drawback, here we present grain-refined Fe 42 Mn 28 Cr 15 Co 10 Si 5 exhibiting significantly high fatigue strength as compared with leading transformation induced plasticity steels upon friction stir processing. The enhanced fatigue behavior is attributed to the metastability-promoted γ → ε transformation that caused local variation in workhardening activity near the crack tip, and subsequent crack branching. Thus, decreased γ phase stability assisted not only in attaining strength but also in making the alloy fatigue-resistant. IMPACT STATEMENT Fatigue resistance of dual-phase TRIP Fe 42 Mn 28 Cr 15 Co 10 Si 5 was evaluated. Metastability-promoted γ → ε transformation improved fatigue life due to local enhancement in work-hardening near the crack tip.

A Focused Review on Engineering Application of Multi-Principal Element Alloy

“…Due to the ultrafine-grained microstructure delays crack initiation whereas the localized transformation within the crack plastic zone delayed crack propagation, the ultrafine-grained microstructure combined with the transformation-induced plasticity is an effective way to design the next generation of fatigue-resistant alloys (Liu et al, 2018(Liu et al, , 2019bTian et al, 2019;Picak et al, 2021). The grainrefined Fe 42 Mn 28 Cr 15 Co 10 Si 5 MPEA prepared by friction stir processing exhibits significantly high fatigue strength, as compared with phase transformation induced plasticity steels (Liu et al, 2018). The ultrafine-grained CoCrFeMnNi MPEA prepared by equal channel angular pressing demonstrates a superior fatigue life at relatively low strain amplitude (Picak et al, 2021).…”

Predicting temperature-dependent ultimate strengths of body-centered-cubic (BCC) high-entropy alloys

“…In contrast to traditional alloys containing only one or two principal elements, multi-principal-element alloys, also referred to as HEAs, have been developed and studied in the recent decade [1][2][3][4][5][6][7] . Carefully designed HEAs with either single or multiple phases have shown encouraging mechanical properties, compared to conventional alloys [8][9][10][11][12][13][14][15][16] .…”

Enhancing fatigue life by ductile-transformable multicomponent B2 precipitates in a high-entropy alloy

“…Recently, a new alloy-design concept, called high-entropy alloys (HEAs), shows great potential in enhancing materials’ mechanical performance 2 – 9 . The diverse characteristics in HEAs, such as severe lattice distortion, multicomponent precipitates, short-range ordering (SRO), and tunable stacking-fault energies (SFE) 10 , 11 , can be utilized to improve materials fatigue performance 12 – 18 . Particularly, atypical ductile multicomponent intermetallic phases, recently observed in HEAs and distinct from brittle intermetallics, can enhance the strength without sacrificing too much ductility 7 , 19 , 20 .…”