Microfracture mechanisms in a 2124 Al-SiC{sub w} composite under dynamic loading
- Pohang Inst. of Science and Technology (Korea, Republic of). Center for Advanced Aerospace Materials
- Changwon National Univ. (Korea, Republic of). Dept. of Materials Science and Engineering
Under very high loading rates, the dominant microfracture mechanism may be different from that under standard testing procedures. In dynamic loading conditions, in which material inertia plays a significant role, analysis of the microfracture behavior in materials that respond in either a nominally elastic manner or a fully plastic manner is quite complicated. Recently, Cho et al. performed the dynamic fracture tests to measure fracture toughness (K{sub Id}) values of 2124 Al composites reinforced with SiC whiskers. They found that the dynamic fracture toughness values were greater than those measured under quasi-static loading. Pickard et al. obtained stress-strain curves at a quasi-static strain rate of 0.0025 sec{sup {minus}1} and an impact rate of 1,500 sec{sup {minus}1} using a fully instrumented Hopkinson bar: yield strength, elastic modulus, and fracture strain were observed to increase with strain rate. From the results of fracture surface observations, Cho et al. assumed that the early stage of microvoid initiation under dynamic loading is similar to that found under quasi-static loading, and analyzed the fracture toughness data. However, this simple assumption may not be applicable in the fracture analysis of the 2124 Al-SiC{sub w} composites, since the microfracture mechanism under dynamic loading may be different from that of the quasi-static case. Moreover, the dynamic fracture mechanics must taken into account the time factor in the toughness calculation. Thus, a more detailed study of the microfracture mechanism of the 2124 Al-SiC{sub w} composite under dynamic loading is required for a fundamental understanding of how microfracture process is affected by loading rates. This is the purpose of this paper.
- OSTI ID:
- 231082
- Journal Information:
- Scripta Metallurgica et Materialia, Vol. 30, Issue 2; Other Information: PBD: 15 Jan 1994
- Country of Publication:
- United States
- Language:
- English
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