Damping capacity of Al–12Si composites effected by negative thermal expansion of Y 2W 3O 12 particle inclusions

摘要

Effects of Y2W3O12particle inclusions and content on damping capacity of Al–12Si composites have been investigated. The Y2W3O12, which is a kind of negative thermal expansion material, can generate high local strain in the composites. Thermal expansion testing shows that the coefficient of thermal expansion (CTE) of Y2W3O12has obvious changes between 100 and 200?°C The Y2W3O12/Al–12Si composites show damping peaks and display higher damping capacities than the pure Al–12Si alloy. The damping capacities of composites strongly depends on the content of Y2W3O12inclusions. A thermal strain damping model is also established. Based on the model analysis results, there is a significant contribution of thermal strain to the damping capacity in the composites; the change in CTE of Y2W3O12could cause the generation of damping peaks. Moreover, dislocation damping and interfacial damping are also main damping mechanisms in the investigated composites.