Research On Properties Of Fe₂B And It's Improvment In Fe Based Alloy

During the process of searching for materials which have immunization in molten zinc, it was found that both Fe₂B phase in borid layer and in Fe-B alloys construct the most to resist corrosion in liquid zinc. Fe₂B is a typical kind of interstitial intermetallic compound, hence it has eigen-brittleness. Its brittleness conduces the alloy a brittle one and results in a bad behaver in liquid zinc. So it is required to put up studies on improving toughness of Fe₂B phase.In this paper different content of Cr, Nb, Zr, La, Ni were added to Fe-8.8B alloy to investigate the effects of these elements on corrosion resistent in molten zinc and mechanical properties of Fe₂B phase. It was found that: the corrosion process of Fe₂B phase in liquid zinc can be formulated as x = 0. 0216t1/2 (x-corrosion depth, t-corrosion time) at 600℃, these elements can do little with the anti corrosion property of Fe₂B; corrosion of liquid zinc to Fe₂B phase is started from cracks which is inherent on Fe₂B; the adding of Cr can improve fracture toughness of Fe₂B phase, because one of the Fe atoms in Fe₂B lattice are substituted by Cr atoms and lead distortion of Fe₂B lattice. When the content of Cr is 0.5%, the fracture toughness of Fe₂B phase reach the maximum 27MPa/m2; the interface combination of Fe₂B phase andα-Fe phase is meliorated by the adding of Ni. The maximum bend strength 420MPa was got when the content of Ni was 1%; Nb, Zr form compounds with other elements and gathered together, compound of Zr as ductile second-phase toughened the alloy.