Paper number 244

FRACTURE TOUGHNESS OF STRUCTURAL SICP-6061AL/6061AL COMPOSITE

Shuyi Qin, Guoding Zhang and Wenlong Wang

State Key Lab. of MMCs, Shanghai Jiao Tong University, Shanghai 200030, China

Summary

A structure-toughened SiC particle reinforced 6061 aluminum alloy matrix composite (SiCp-6061Al/6061Al) was designed and fabricated by vacuum infiltration processing. Its fracture toughness KQ was tested by three-point bending method and compared with a conventionally stirring-cast SiCp/6061Al composite's in case of same particle size and volume fraction. The fractography of the SiCp-6061Al/6061Al composite was observed on a Cambridge Instrument S360 Scanning Electron Microscopy (SEM). The results showed that SiCp-6061Al/6061Al composite has a higher fracture toughness KQ but a lower yield strength and a comparative elastic modulus. The crack opening displacement (COD) vs load curve of the designed composite showed that the fracture procedure of SiCp-6061Al/6061Al composite is by three stages and the maximum load on it can maintain for a long time. The deformation of the unreinforced 6061Al matrix and the SiCp-6061Al/6061Al interface debonding toughen this composite cooperatively. The complete fracture procedure of the designed composite was schemed by a model. This kind of composite can avoid abrupt failure occurring in most other conventional composite.

Keywords

aluminum-matrix composites, fracture toughness, interface structural.