Processing and Characterization of CrB2-Based Novel Composites

Abstract

This paper presents the results of investigations carried out on processing and characterization of CrB2-based novel composites. Niobium metal powder was used as additive to form new composites. Hardness and fracture toughness of chromium boride increased by addition of niobium. CrB2 composites were prepared by addition of 2.5, 10 and 20 wt.% Nb. Density of higher than 95% ρth was achieved in all the samples. Hot pressed samples were analyzed to contain reaction products of NbB2, Cr2B3 and Cr3B4 phases along with CrB2. Hardness of CrB2 composite was increased from 18.46 GPa to 21.89 GPa by increasing the Nb content from 2.5 to 10 wt.%. Fracture toughness of composites prepared by addition of 2.5 and 10% was measured as 3.11 and 3.38 MPa.m1/2 respectively. Addition of 20% Nb resulted in increased fracture toughness of 4.32 MPa.m1/2.

Keywords

• crb2
• densification
• niobium
• hardness
• fracture toughness
• hot pressing