Influence of B4C Content on Flexural Performance of Ni + B4C Microwave Composite Clads

摘要

This study focused on the development of microwave composite cladding of a Ni-based alloy reinforced with varying proportions (wt.%) of B4C such as 0, 5, 10 and 20% on a SS-304 steel substrate. Clads showed metallurgical bonding with the substrate by the partial dilution of the materials. Various techniques of characterization confirmed the formation of hard phases of borides and carbides such as Fe23B6, Fe5C2, Cr7C3, Cr7BC4 and their distribution in the Ni matrix throughout the clad volume. Flexural performance tests of the clads were done using a three-point bend test at a deformation rate of 0.5 mm/min, and composite clad reinforced with 10% B4C showed the highest flexural strength that was observed to be 479 +/- 13 MPa. Clads failed in the upper transition load, and a sudden load drop was observed at the failure points of the clads. Fractography revealed that reinforced phases provided sufficient strength to the Ni-based ductile matrix because crack propagation in the clads was arrested by these hard phases while deformation.