Influence of Nb on the Microstructure and Fracture Toughness of (Zr0.76Fe0.24)100-xNbx Nano-Eutectic Composites

Tapabrata Maity; Anushree Dutta; Parijat Pallab Jana; Konda Gokuldoss Prashanth; Jürgen Eckert; Jayanta Das

doi:10.3390/ma11010113

Influence of Nb on the Microstructure and Fracture Toughness of (Zr_0.76Fe_0.24)_100-xNb_x Nano-Eutectic Composites

Materials (Basel). 2018 Jan 11;11(1):113. doi: 10.3390/ma11010113.

Authors

Tapabrata Maity^{1

2}, Anushree Dutta³, Parijat Pallab Jana⁴, Konda Gokuldoss Prashanth^{5

6}, Jürgen Eckert^{7

8}, Jayanta Das⁹

Affiliations

¹ Department of Materials and Metallurgical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India. tapabrata.maity@unileoben.ac.at.
² Department of Materials Physics, Montanuniversitat Leoben, Jahnstrasse 12, 8700 Leoben, Austria. tapabrata.maity@unileoben.ac.at.
³ Department of Materials and Metallurgical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India. anushree032003@yahoo.co.in.
⁴ Department of Materials and Metallurgical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India. parijat.pallab@iitkgp.ac.in.
⁵ Department of Manufacturing and Civil Engineering, Norwegian University of Science and Technology, Teknologivegen 22, 2815 Gjøvik, Norway. kgprashanth@gmail.com.
⁶ Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstraße 12, A-8700 Leoben, Austria. kgprashanth@gmail.com.
⁷ Department of Materials Physics, Montanuniversitat Leoben, Jahnstrasse 12, 8700 Leoben, Austria. juergen.eckert@unileoben.ac.at.
⁸ Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstraße 12, A-8700 Leoben, Austria. juergen.eckert@unileoben.ac.at.
⁹ Department of Materials and Metallurgical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India. j.das@metal.iitkgp.ernet.in.

Abstract

The present study demonstrates the evolution of eutectic microstructure in arc-melted (Zr_0.76Fe_0.24)_100-xNb_x (0 ≤ x ≤ 10 atom %) composites containing α-Zr//FeZr₂ nano-lamellae phases along with pro-eutectic Zr-rich intermetallic phase. The effects of Nb addition on the microstructural evolution and mechanical properties under compression, bulk hardness, elastic modulus, and indentation fracture toughness (IFT) were investigated. The Zr-Fe-(Nb) eutectic composites (ECs) exhibited excellent fracture strength up to ~1800 MPa. Microstructural characterization revealed that the addition of Nb promotes the formation of intermetallic Zr₅₄Fe₃₇Nb₉. The IFT (K_IC) increases from 3.0 ± 0.5 MPa√m (x = 0) to 4.7 ± 1.0 MPa√m (x = 2) at 49 N, which even further increases from 5.1 ± 0.5 MPa√m (x = 0) and up to 5.9 ± 1.0 MPa√m (x = 2) at higher loads. The results suggest that mutual interaction between nano-lamellar α-Zr//FeZr₂ phases is responsible for enhanced fracture resistance and high fracture strength.

Keywords: electron microscopy; eutectic alloys; indentation fracture toughness; mechanical properties; microstructure.