| Title |
Dynamic Fracture mechanism of a 2124 Al - SiCw Composite |
| Authors |
이창길(Chang Gil Lee); 이성학(Sung Hak Lee); 권동일(Don Gil Kwon) |
| Abstract |
Abstract An investigation was conducted into the effects of loading rate on the fracture initiation of 2124 Al composite reinforced with SiC whiskers. Dynamic void initiation tests were carried out at room temperature using round notch specimens loaded in tension with a strain rate of about 10³/sec, and were compared with those for quasi-static loading. Detailed fractographic observations and cross-sectional microstructure analysis were also made to identify local micromechanical processes of void or crack initiation. One of the important results is that the void initiation sites of the composite are strongly influenced by the loading rate: voids initiate at whisker ends under quasi-static loading and at whisker sides under dynamic loading. Futhermore, the favored direction of crack growth is also dependent upon the loading rate, i.e, approximately 45 degrees under quasi-static loading rate and perpendicular to the tensile axis under dynamic loading rate. Such different local fracture processes with the different Loading rates are interpreted in terms of the role of SiC whiskers on the load carrier in the 2124 Al-SiC_w composite. |