Microstructural design by severe warm-rolling for tuning mechanical properties of AlCoCrFeNi2.1 eutectic high entropy alloy
Journal article, 2019

The influence of severe warm-rolling and subsequent annealing on the microstructure and mechanical properties in an AlCoCrFeNi2.1 high entropy alloy consisting of a lamellar arrangement of ordered L1(2) and B2 phases was studied. For this purpose, the as-cast EHEA was severely warm-rolled up to 90% reduction in thickness at selected temperatures of 400 degrees C, 600 degrees C, and 750 degrees C. The severely warm-rolled EHEAs were further annealed at temperatures ranging from 800 degrees C to 1200 degrees C for 1 h. Warm-rolling resulted in a unique disordering behavior of the L1(2) depending on the temperature of warm-rolling. However, the B2 phase maintained the ordered structure irrespective of the warm-rolling temperature. The EHEA warm-rolled at 400 degrees C and 600 degrees C showed a predominantly lamellar microstructure, while the EHEA warm-rolled at 750 degrees C showed a novel heterogeneous microstructure featured by a mixture of lamellar and non-lamellar regions. Annealing of the 90% warm-rolled materials resulted in the formation of predominantly duplex microstructures consisting of disordered FCC and B2 phases. The EHEA warm-rolled at 400 degrees C and 600 degrees C showed high strength but rather limited ductility, which could be improved upon annealing. Remarkably, the EHEA warm-rolled at 750 degrees C showed the most outstanding properties featured by exceptional strength-ductility combination owing to the novel heterogeneous microstructure. Annealing of the heterogeneous EHEA resulted in the deterioration of the strength-ductility balance owing to the annihilation of the heterogeneous microstructure, being replaced by a microduplex structure.

TEM

High entropy alloy

Deformation

Tensile properties

EBSD

Annealing

Author

Rajasekhar Reddy Seelam

IIT Hyderabad

Upender Sunkari

IIT Hyderabad

Adrianna Lozinko

Chalmers, Industrial and Materials Science, Materials and manufacture

Rajib Saha

Tata Steel

Sheng Guo

Chalmers, Industrial and Materials Science, Materials and manufacture

Pinaki Prasad Bhattacharjee

IIT Hyderabad

Intermetallics

0966-9795 (ISSN)

Vol. 114 nov. UNSP 106601

Subject Categories

Ceramics

Other Materials Engineering

Metallurgy and Metallic Materials

Areas of Advance

Materials Science

DOI

10.1016/j.intermet.2019.106601

More information

Latest update

6/28/2021