Effect of interfacial microstructure and mechanical properties of steel/copper casting bimetal by active protective agent

This article study on the 45#steel/high-lead tin bronze bimetal that were prepared by solid-liquid casting. Effect of interfacial microstructure and mechanical properties by active protective agents were investigated including Na2B4O7, H3BO3, AlPO3 and NaF. The results show that the effect of the single component active protective agent on the binding interface is Na2B4O7>H3BO3>AlPO3>NaF. The multiple components optimal ratio of the active protective agent is Na2B4O7:H3BO3:AlPO3:NaF=60:25:10:5(wt.%)after mixing, which make the interfacial bonding strength reach 168.4 MPa and diffusion distance of the Fe/Cu interface attain 12.4μm. When the thickness of Na2B4O7 is lower than 60%, FeP transition layer is precipitated at the interface, which depress the interface shear strength.