High Boron Iron-Based Alloy and Its Modification

High boron iron-based alloy, a new kind of wear-resistant material was developed, and its microstructure and mechanical properties were studied. Moreover, the modification with V, Ti and RE-Mg was carried out as well. The results indicate that the high boron iron-based alloy comprises a dendritic matrix and interdendritic eutectic bo-rides under as-cast condition. The matrix is made up of fine pearlite, and the eutectic boride has a crystal structure of M2B (M represents Fe, Cr or Mn). The boride has a microhardness of HV 1 425 and is distributed in the form of continuous network, which is detrimental to the toughness of high boron iron-based alloy. Nevertheless, high boron iron-based alloy has a higher toughness than that of white cast iron, which is attributed to the matrix that is made up of lath-type martensite with high toughness. In order to increase the toughness further, V, Ti and RE-Mg were adopted to improve the morphology of boride. The results indicate that after modification the matrix grain is decreased in size by half, and the size of boride is also decreased, moreover, it is distributed more even though it is still continuous. After heat treatment, the boride network is break up and results in the further improvement of toughness of high boron iron-based alloy.