The Effect of Sc on the Tolidification Ticrostructure and Wear Resistance of Al-Bi Partial Crystalline Alloys
The effects of rare earth element Sc on the solidification structure and wear resistance of Al-Bi partial crystal alloy were studied by microalloying method.The samples were tested and characterized by OM,SEM,TEM,multifunctional surface properties tester and other equipment.The results show that the addition of trace Sc element reduces the form energy of the Bi-rich phase and increases the nucleation position.It effectively eliminates the component segregation of the Bi-rich phase,and reduces the grain size of the Al matrix.At the same time,trace Sc element can significantly improve the hardness and friction coefficient of Al-Bi alloy,when the content of Sc is 0.25 wt％,the hardness and friction coefficient can reach the maximum value.Compared with without Sc,the hardness is increased by 109％,and the friction coefficient is increased by 33％.When the content of Sc increased to 1 wt％,a dense Al3 Sc phase was found in the sample,with a regular geometric profile and obvious segregation behavior.The two phases of Bi-rich phase and Al3 Sc phase are precipitated separately and do not interfere with each other.
partial crystalline alloymicrostructurecoefficient of frictionprecipitated phase
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