Research On Toughness And Mechanim Of Intermetallic Compound Fe₂B

Fe₂B is a typical kind of intermetallic compounds with the best behavior on corrosion resistance to molten zinc and eigen-brittleness.This restricts the industry application for Fe₂B on high temperature structure materials.So it is required to put up studies on improving toughness of Fe₂B.In this paper,the valence electron structure of (Fe_1-xCr_x)₂B has been calculated on basis of solid and molecule's empirical electron theory and average atom model.Then tests on Fe-8.8B-XCr(Mn or La) samples were put into effect for its mechanical properties.The results show that,there's little effects on the structure of samples or microhardness of Fe₂B including Cr or Mn or La.There're also Fe₂B andα(including little C or Si) and microhardness is proximity 1100HV0.1.The bending strength of (Fe,Cr)₂B can be raised from 203 MPa to 387MPa.There're increasing effects on the fracture toughness of samples, especially for Cr,K_Ic can be increased from 28.61 M Pam^1/2 to 65.85 M Pam^1/2.After calculation,it was found that the B-B bond energy increased from 5.6574 kJ/mol to 79.0047 kJ/mol obviously,which can lessen occurrence of initial cracks.It was found that the crystallographic orientation of fracture plane in Fe-8.8B is {110}.For samples including Cr,it needs 342.0531 kJ/mol to crack along (110),which is greater than Fe₂B.