Processing and Characterization of CrB_2-Based Novel Composites

摘要

This paper presents the results of investigations carried out on processing and characterization of CrB_2-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. CrB_2 composites were prepared by addition of 2.5, 10 and 20 wt.% Nb. Density of higher than 95% ρ_(th) was achieved in all the samples. Hot pressed samples were analyzed to contain reaction products of NbB_2, Cr_2B_3 and Cr_3B_4 phases along with CrB_2. Hardness of CrB_2 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.m~(1/2) respectively. Addition of 20% Nb resulted in increased fracture toughness of 4.32 MPa.m~(1/2).