Abstract:The microstructures and damping capacity of AZ91D cast alloys containing various Ce contents were investigated. Damping capacity (Q^-1) of the alloys was measured by cantilever beam technique, and the relationship between damping capacity and strain amplitude was investigated. The results show that Al4Ce phase is formed in AZ91D alloy after adding a certain quantity of Ce contents, then as-cast microstructures of the alloys are refined. Meanwhile the damping capacity of the alloys is also improved. When the mass fraction of Ce is 0.7%, the most obvious refinement effect and the maximum damping capacity can be obtained. When the damping capacity (Q^-1) is 2.728×10-³, 61% increment can be obtained compared with unmodified AZ91D alloy. The damping capacity of the alloys is relative to strain amplitude,and the damping behavior can be explained by the theory of Granato and Lücke.

Key words: damping capacity; damping mechanism; AZ91D alloy; Ce modification