Study On The Effects Of Rare Earth On Microstructure And Properties Of High Boron Iron-based Fe2.5B0.43Calloy

High boron iron-based alloy is a new type of wear-resistant material, it has high hardness and well wear-resistance, but the boron element in mesh easily forms reticular boride along the grain boundary, leading to be lack of plasticity and toughness. In this paper, basing on the optimization of the three elements of B,C,Cr, used the modifier modification attempting to improve the boride morphology and disturb the boride mesh into disconnected and isolated structure and improve the properties of high boron iron-based Fe2.5B0.43C wear-resistant alloy, and then delved into the effect of RE Ce-La, RE-Mg and RE-Si three kinds of modification and their adding contents on high boron iron-base alloy’s microstructure and properties (Hardness, Impact tounghness, Bending strength, Deflection). The results were as follows:XRD analysis indicated that:In the high boron iron-based Fe2.5B0.43C alloy mainly presented three phases a-Fe, M2Bå'ŒM3(B,C), M represented Cr,Mn,V etc. M2B had orthorhomibic crystal structure and was main hard and wear resistant phase in the alloy. SEM and EDS analysis:The high boron iron Fe2.5B0.43C alloy was made up of matrix and eutectic boride, matrix was mainly composed of lamellar pearlite and ferrite, eutectic boride was mainly composed of M2B and M3(B,C).Ferrite presented mainly around the boride.Different alloy elements had different distribution in the alloy.When researched the modification effect of three kinds modifiers RE Ce-La RE-Mg, RE-Si and their different adding amount on high boron iron-based Fe2.5B0.43C wear-resistant alloy, found that:Three kinds of modifiers both had good effect on the high boron iron-based wear resistant alloy,and the boride had different disconnection or necking,especially the effect of1.0%RE Ce-La and2.0RE-Si modification:The microstructure of alloy were greatly refined,and boride was very fine and largely disturbed, so it obiviously eliminate the gross boride and reduced the boride presenting on the boundary of theg rain, then reduced the splitting of the marix,so the material reached the optimal comprehensive mechanical properties:The flexural strength was1238.61360.MPa, hardness was66.3HRC～70.2HRC, impact toughness was6.38～7.12J/cm2, inflection was1.70～1.71mm,it was much higher than those no modification (Flexural strength was645.3MPa, Hardness was52HRC, Impact toughness was3.36J/cm2, the deflection was0.42mm).