Age Hardening of the Al0.5CoCrNiTi0.5 High-Entropy Alloy

Al0.5CoCrNiTi0.5 high-entropy alloy was synthesized by vacuum arc melting in a copper mold. This alloy was aged at 773 K to 1473 K (500 °C to 1200 °C) for 24 hours to investigate the microstructure and hardness. The hardness of the as-cast alloy is HV743, and it exhibits a dendritic structure, in which dendrite is composed of body-centered cubic (bcc), face-centered cubic (fcc), and σ phases, and interdendrite is an eutectic structure consisting of bcc and order bcc phases. Apparent age hardening appears at 873 K to 1173 K (600 °C to 900 °C), and no age softening occurs even after 1473 K (1200 °C) aging. The age hardening of this alloy is attributed to the transformation of the bcc phase to σ phase. Detailed variations of hardness and the microstructure of aged alloys are reported in this article.

[1]  J. Yeh,et al.  Microstructure and mechanical property of as-cast, -homogenized, and -deformed AlxCoCrFeNi (0 ≤ x ≤ 2) high-entropy alloys , 2009 .

[2]  P. Liaw,et al.  Solid‐Solution Phase Formation Rules for Multi‐component Alloys , 2008 .

[3]  Jing Shi,et al.  Microstructure and mechanical properties of CoCrFeNiTiAlx high-entropy alloys , 2009 .

[4]  Yong Zhang,et al.  Microstructure characterizations and strengthening mechanism of multi-principal component AlCoCrFeNiTi0.5 solid solution alloy with excellent mechanical properties , 2008 .

[5]  Andrew G. Glen,et al.  APPL , 2001 .

[6]  J. Yeh,et al.  Mechanical performance of the AlxCoCrCuFeNi high-entropy alloy system with multiprincipal elements , 2005 .

[7]  Y. Zhou,et al.  Solid solution alloys of AlCoCrFeNiTix with excellent room-temperature mechanical properties , 2007 .

[8]  J. Yeh,et al.  Microstructure characterization of AlxCoCrCuFeNi high-entropy alloy system with multiprincipal elements , 2005 .

[9]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[10]  T. Shun,et al.  Nanostructured High‐Entropy Alloys with Multiple Principal Elements: Novel Alloy Design Concepts and Outcomes , 2004 .

[11]  T. Shun,et al.  The effects of secondary elemental Mo or Ti addition in Al0.3CoCrFeNi high-entropy alloy on age hardening at 700 °C , 2010 .

[12]  Jinshan Li,et al.  Effect of aging temperature on microstructure and properties of AlCoCrCuFeNi high-entropy alloy , 2009 .

[13]  T. Chin,et al.  Formation of simple crystal structures in Cu-Co-Ni-Cr-Al-Fe-Ti-V alloys with multiprincipal metallic elements , 2004 .

[14]  P. Liaw,et al.  High-entropy Alloys with High Saturation Magnetization, Electrical Resistivity, and Malleability , 2013, Scientific Reports.