The damping behavior of a model ferroelastic-reinforced-metal matrix composite (FR-MMC) system was examined through the incorporation of barium titanate (BaTiO 3 ) particles into a Cu-10 wt pct Sn (bearing bronze) matrix. The damping properties of the resulting FR-MMC were investigated vs frequency, temperature (above and below the Curie temperature of the ferroelastic reinforcement), and number of strain cycles. Dynamic mechanical analysis (DMA) indicates that the incorporation of the ferroelastic-capable reinforcement significantly augments the damping capability relative to the matrix alone, and also with respect to the damping that would result from the presence of passive composite reinforcements. Neutron diffraction data demonstrate a strong correlation of domain reorientation activity to imposed stress level and demonstrate a degree of reversibility important to the potential practical application of this mechanism of damping.
Cryogenic mechanical alloying (CMA) has been shown to be an effective means for producing composite powders for selective laser sintering (SLS). Unlike composite particles made by a coating process, both phases are continuous throughout the particles formed by CMA. Consolidation of these composite particles via SLS offers the possibility of forming parts with a co-continuous microstructure. In this research, the microstructure of mechanically alloyed polymer-polymer composites for use in the SLS process is investigated using transmission electron microscopy. By varying the charge ratio and milling time of the CMA process, the phase domain size of the resulting composite powder can be manipulated. This ongoing work explores the microstructural evolution as the composite powders are consolidated via SLS into macroscopic parts, as well as the relationships between microstructure and bulk properties.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.