Narrow Results

Ethylene Propylene Diene Monomer (EPDM) composites filled with 0–400 phr ${\mathrm{\text{PbWO}}}_4$ (PWO) were prepared by conventional process using a two-roll mill. Surface treatment of the fillers coated with KH570 was conducted to enhance the wettability and lubrication of fillers in the polymer matrix. According to SEM images and mechanical test, both micro- and submicro-fillers disperse homogeneously in the matrix, and adhesion of submicro-fillers to the matrix is stronger than that of micro-fillers. The submicro-PWO composites had better tensile strength and elongation at break than those composites containing micro-PWO powder, but a relatively higher hardness. The photon shielding test was performed to determine the radiation shielding properties of these composites, which showed that attenuation of gamma-rays for the submicro-PWO composites was substantially enhanced compared to micro-PWO reinforced composites.

This experiment chooses A356 aluminum matrix composites containing 55% SiC particle reinforcing phase as the parent metal and Al–Si–Cu–Zn–Ni alloy metal as the filler metal. The brazing process is carried out in vacuum brazing furnace at the temperature of 550°C and 560°C for 3 min, respectively. The interfacial microstructures and fracture surfaces are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy spectrum analysis (EDS). The result shows that adequacy of element diffusion are superior when brazing at 560°C, because of higher activity and liquidity. Dislocations and twins are observed at the interface between filler and composite due to the different expansion coefficient of the aluminum alloy matrix and SiC particles. The fracture analysis shows that the brittle fracture mainly located at interface of filler and composites.