Details

Autor(en) / Beteiligte

• Chang, H.
• Zhang, T.W.
• Ma, S.G.
• Zhao, D.
• Bai, T.X.
• Wang, K.
• Li, Z.Q.
• Wang, Z.H.

Titel

Strengthening and strain hardening mechanisms in precipitation-hardened CrCoNi medium entropy alloys

Ist Teil von

• Journal of alloys and compounds, 2022-03, Vol.896, p.162962, Article 162962

Ort / Verlag

Lausanne: Elsevier B.V

Erscheinungsjahr

2022

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •The strength of CrCoNi MEA was significantly increased when maintaining a considerable elongation in CrCoNiSi0.2Al0.2 MEA.•The σ + B2 precipitation strengthening structure was formed in CrCoNiSi0.2Al0.2 MEA.•It is the Orowan + shearing precipitation hardening mechanisms that improved the strength and strain hardening capacity.•Orowan mechanism is more effective on improving strain-hardening capacity than shearing mechanism. [Display omitted] The CrCoNiSixAlx (x = 0.1, 0.2) medium entropy alloys (MEAs) were designed to achieve significant improvement in strength and strain hardening via the minor addition of Si and Al elements to the CrCoNi MEA. The B2 + σ precipitation structure was formed on the CrCoNiSi0.2Al0.2 MEA. Compared to CrCoNi MEA, the yield and ultimate tensile strengths of the CrCoNiSi0.2Al0.2 MEA enhanced from 380 MPa to 850 MPa and 790–1287 MPa, respectively, while the uniform elongation was 23±5% that outperformed various advanced steels and Al-added MEAs/HEAs. The Orowan+shearing precipitation hardening mechanisms together with the deformation twins in a face-centered cubic (FCC) matrix were identified to improve the strength and strain hardening capacity. These findings provide guidance for the development of precipitation-hardened MEAs/HEAs with strength-ductility synergy.